# Ca and Mg again



## DarioU (May 15, 2014)

Dear Orchids friends, Excuse me for my bad English. I need to supplement my fertilization with Ca and Mg but How is not clear. I have read very much but the argument is not clear at all.
Can I supplement Ca and Mg only with Ca nitrate and Mg nitrate for a long time ?
Can I mix in the same solution, in the right doses of course, Ca nitrate and Mg nitrate?
Because both (Ca and Mg) are in their nitrate form perhaps I can mix them, I think. 
Can add Ca nitrate and Mg nitrate in Fertilizing solution or I must keep them separate?
If I mix them with the fertilizing solution the P precipitate them resulting in P, Ca and Mg deficience?
I have read all and the contrary of all.
Thank you for your help and answers
Dario


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## Brabantia (May 15, 2014)

You can mix Calcium nitrate and Magnesium nitrate in solution without problems.
The ratio Ca/Mg must be between 3 and 4. You can added this solution to your fertilyser solution by taking into account brought quantities of Nitrogen by Calcium nitrate and Magnesium nitrate. By using the usual concentrations in Phosphorus for Paph's (5 to 10 ppm or less) you will have no problems with Calcium phosphate precipitation.


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## Ozpaph (May 15, 2014)

Every month instead of my usual fertiliser I use either a level teaspoon of magnesium sulphate (Epsom salts) OR Calcium nitrate to 5 litres of water and apply. My usual fertiliser does have both elements.


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## DarioU (May 18, 2014)

Thank you very much


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## Rick (May 19, 2014)

Why do you think you need to supplement Ca and Mg?

Also if you supplement with potassium more than 10 ppm, adding Ca and Mg is a waste of time since the potassium will block the Ca and Mg uptake even if you add Ca to more than 200ppm.


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## Stone (May 20, 2014)

Rick said:


> > Also if you supplement with potassium more than 10 ppm, adding Ca and Mg is a waste of time since the potassium will block the Ca and Mg uptake even if you add Ca to more than 200ppm
> 
> 
> 
> ...


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## DarioU (May 20, 2014)

Thank you for your answers. I need to supplement Ca and Mg because my well water has too much Na and so I use RO water. My fertilizer has very low content of Ca and Mg and I have some problems with buds. I use N/K about 3:1.


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## Stone (May 20, 2014)

DarioU said:


> Thank you for your answers. I need to supplement Ca and Mg because my well water has too much Na and so I use RO water. My fertilizer has very low content of Ca and Mg and I have some problems with buds. I use N/K about 3:1.



Just do as Ozpaph does or put the Calnitrate and Magsulphate into your regular (diluted) fert mix and dilute until you're happy with the EC. If you're worried about diluting the trace elements too much you can use K-lite to mix with your regular feed as I do occasionally. In fact K-lite is very handy for that! It will make a regular high ammonium/urea/no Ca mix into potentially better fertilizer by reducing P and K (if you want to do that) and increasing Ca, Mg and nitrate and keep the minor elements fairly constant.


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## Rick (May 20, 2014)

Stone said:


> Rick said:
> 
> 
> > Sorry but I must strongly disagree. If this were true, we would be seeing deficienies all over the place..
> ...


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## DavidCampen (May 21, 2014)

Rick said:


> ... if you supplement with potassium more than 10 ppm, adding Ca and Mg is a waste of time since the potassium will block the Ca and Mg uptake even if you add Ca to more than 200ppm.


There is not scientific evidence to justify that statement.


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## gonewild (May 21, 2014)

DavidCampen said:


> There is not scientific evidence to justify that statement.



Prove there is no evidence.


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## Stone (May 21, 2014)

gonewild said:


> Prove there is no evidence.



No need!


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## gonewild (May 21, 2014)

Stone said:


> No need!



Nor is there a need to prove it to you, so quite asking for scientific proof.

The frequent, limited "there is no scientific proof" statements just confuse people that want advice about growing orchids rather than bio/chemistry.


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## Stone (May 22, 2014)

gonewild said:


> Nor is there a need to prove it to you, so quite asking for scientific proof.
> 
> 
> 
> ...


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## DavidCampen (May 22, 2014)

gonewild said:


> Nor is there a need to prove it to you, so quite asking for scientific proof.



I ask for proof only because you and Rick keep making claims that it exists. Quit making claims that this potassium toxicity conjecture is anything more than a conjecture without scientific basis and I will quit pointing out that there is no scientific basis for this conjecture.


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## gonewild (May 22, 2014)

DavidCampen said:


> I ask for proof only because you and Rick keep making claims that it exists. Quit making claims that this potassium toxicity conjecture is anything more than a conjecture without scientific basis and I will quit pointing out that there is no scientific basis for this conjecture.



This is not a science forum. This is a forum about growing orchids. This is not a plat form to prove or disprove anything.

What value do you add to the forum if all you do is say "there is no proof"?
Tell us about your personal experience or observations that might cause us to change our minds.

Personally I want to spend my time directly in contact with plants not googling for proof that does not exist to prove either side. There will never be scientific proof one way or another. But there is proof based on hands on experience.

So David what have you done towards using a low K fertilizer that has proven to you that it is a bad idea?

It would be much more enjoyable for 99% of ST members to read about other growers experience rather than arguments about scientific proof.

So again, seriously, have you had issues with your plants not growing well due to a lack of Potsassium?


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## DavidCampen (May 22, 2014)

gonewild said:


> So David what have you done towards using a low K fertilizer that has proven to you that it is a bad idea?


I wouldn't use a low K fertilizer. It seems an absurd idea.



gonewild said:


> It would be much more enjoyable for 99% of ST members to read about other growers experience rather than arguments about scientific proof.


I would not disagree with that but someone who posts here and even in this thread; wrote a pseudo scientific article promoting his potassium toxicity conjecture in a way that would make it seem to the casual reader that he was offering scientific evidence that his conjecture was correct. And he continues to this day to make posts here, as recently as a couple of days ago, that would lead the casual reader to believe that there is scientific evidence for this potassium toxicity conjecture when there is not. I think that it would be great if certain people would quit trying to claim and imply that there is scientific evidence for this potassium toxicity conjecture.



gonewild said:


> So again, seriously, have you had issues with your plants not growing well due to a lack of Potsassium?


I don't use a low K fertilizer. I think that it is a patently absurd idea.


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## Rick (May 22, 2014)

https://www.msu.edu/~warncke/E0486.pdf

Michigan State University seems to be pretty comfortable with the concept of K antagonism. Where's their proof or does MSU deal in pseudoscience?
(note this is a 1994 document, and K antagonism articles go back a lot farther than that)

They don't want to commit to any numbers except "do what you want as long as you don't go outside of the sufficiency standards"
(also note they use the term "toxicity" for exceeding the sufficiency standards at least once in this document)

The section on Mg is interesting in that they indicate that the soil equivalents of Mg must be equal or greater that of K and then Ca can be up to 10X greater than Mg.

The step I went beyond MSU was substituting the insitu (jungle) leaf tissue concentrations of NPK /Ca/ Mg for the agri-based sufficiency standards and extrapolating the eco-relevant concentrations of those nutrients into an application plan (that works).


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## mrhappyrotter (May 22, 2014)

Oh dear baby Jesus. Do you want unresolved and heated 100+ comment threads? Because this is how you get unresolved and heated 100+ comment threads.


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## Stone (May 22, 2014)

Rick said:


> > The step I went beyond MSU was substituting the insitu (jungle) leaf tissue concentrations of NPK /Ca/ Mg for the agri-based sufficiency standards and extrapolating the eco-relevant concentrations of those nutrients into an application plan (that works).
> 
> 
> 
> ...


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## Ray (May 23, 2014)

I still contend that these ratios are not all THAT important, as we're probably - even at really low fertilizer concentrations - giving out plants WAY more nutrients than they really need, so they are getting "enough" of everything despite the appearance of imbalances or antagonism.

I was concerned about deficiencies using K-Lite, but for what it's worth, I've been using the K-Lite formula exclusively since late November of 2011. I feed at about 35 ppm N 2-3x/week, depending upon the weather. Monthly I supplement with KelpMax at 1:256. KelpMax does have some nutrients in it, including potassium. My plants have never done better.

Most of my paphs, as I have said before, have gone from 1-, maybe 2 new growths per cycle to 3-, 4-, or 5, and they are getting bigger, faster. I had spikes out the ying-yang a couple of months ago, but mice "helped" me get rid of those...


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## gonewild (May 23, 2014)

Stone said:


> Rick said:
> 
> 
> > But the leaf tissue data or leaf litter data or throughfall data or Stemflow data or rainfall data or soil data or any other data does not have N at 10 times the K as K-lite does. I think this is an important point. Throughfall and stemflow are the major pathways for K so when it rains, soil water (terrestrial and epiphytic) is heavily charged with K. A paph growing at the base of a tree or in a bamboo grove or even in moss on a rock, which apparently many do, will have access to plenty of K, not in concentration, but in relation to other cations at that time (growing time).
> ...


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## gonewild (May 23, 2014)

Ray said:


> I still contend that these ratios are not all THAT important, as we're probably - even at really low fertilizer concentrations - giving out plants WAY more nutrients than they really need, so they are getting "enough" of everything despite the appearance of imbalances or antagonism.



Ray your contention makes perfect sense. But I disagree, I think the ratio balances are very important.

Nutrient balance and nutrient ratios are extremely important to all life forms. Diet is critical to your dogs health, your birds health, your fishes health, your child's health and your own health. Micro organisms must have a very specific nutrient supply or they don't flourish (starve a cold, feed a fever).

Some how people feel plants are different and just grow. I don't see any reason to believe that plants as living organisms have any less need for the proper nutrient ratios than other organisms.

The problem is "Orchids" is a generic term for perhaps 10,000 different species under cultivation. We want to have one balanced diet that will be perfect for 10,000 different species! Each orchid species has evolved uniquely differently from others and diet may well be a major factor in why one species evolved away from another.

In reality the nutrient ratios are probably the most important factor....and the only one we can't figure out.


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## Rick (May 23, 2014)

Stone said:


> But the leaf tissue data or leaf litter data or throughfall data or Stemflow data or rainfall data or soil data or any other data does not have N at 10 times the K as K-lite does. I think this is an important point......So reducing the N in K-lite will actually get you closer to nature and ..... closer to a ''regular fertilizer. (except for the Ca)



Agreed, stemflow data has everything very dilute. Recall the history of Klite as a concept trial looking into the K antagonism question (no-one ready to give up their N 2 years ago).

But 2 other points.
1) As Lance points out, between BG algae (in mosses or lichens) or other nitrogen fixing organisms, there is an N pipeline that transcends stemflow.
2) I think need to make a distinction between N as nitrate and N as ammonia. Nitrate is considerably less active and benign in the system, and with regard to K lite use results has demonstrated to not be important in a set ratio with K, Ca, Mg (it's offered well beyound excess and is just a pass through with regard to the plants). If the % of ammonia was increased I'd get more excited about the total N in the fert, and actual plant physiology/ratios issues.

Subsequently it wouldn't hurt my feelings to cut it back (note that I feed at 10ppm or less N anyway with good results). The amount of live moss in my systems has been increasing dramatically (I also think from reduced K).

At least with regard to nitrate all the excess is more of a pot managment issue rather than a physiology issue.


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## AdamD (May 23, 2014)

After reading this entire thread in one sitting I've scientifically deduced that you all have way too much time on your hands. Why can't we agree to disagree? Don't shove your point of view down someone elses throat. This isn't church. We're not trying to convert people here. Do what works for you. Share your experiences and results. Let people decide for themselves what to take from it and what to leave. Please. You're turning people off to your points of view by arguing them so abrasively. 

Thanks
The 99%


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## gonewild (May 23, 2014)

AdamD said:


> After reading this entire thread in one sitting I've scientifically deduced that you all have way too much time on your hands. Why can't we agree to disagree? Don't shove your point of view down someone elses throat. This isn't church. We're not trying to convert people here. Do what works for you. Share your experiences and results. Let people decide for themselves what to take from it and what to leave. Please. You're turning people off to your points of view by arguing them so abrasively.
> 
> Thanks
> The 99%



Don't you watch the news? 
The 99% never get what they want (or deserve).
:rollhappy:


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## orcoholic (May 23, 2014)

Ray said:


> I had spikes out the ying-yang a couple of months ago, but mice "helped" me get rid of those...



It would be very helpful if you could tell us exactly where the ying-yang is located. Is it a high light location or low light? Warm, Int, or Cool. I need the facts, Ray, and nothing but the facts.


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## Ray (May 23, 2014)

I agree that there's no need for the rudeness, Adam, but it can still be a fun mental exercise!

Lance - I have no doubt that ratios are important, but if I may extend your human analogy, a person in a grocery store isn't going to eat everything there.

Let's consider just how much of those "groceries" a plant takes up:

This morning, I divided a vanda, and had 5 bare-root divisions. I measured their total root lengths, weighed them as-is, immersed them in 80°F water until the velamen was mostly transparent, and weight them again. On average, they weighed 101 g dry, 107 g "saturated", and had an average root length of 70".

So if I assume 10 waterings per month @ 3 ppm K, plus one at 25 (from the KelpMax), my plants are being exposed to something in the neighborhood of 5 ppm K on average. That 6 g of absorbed liquid, containing 5 ppm K, would carry 30 µg K. If it has absorbed that consistently over it's 10-year life, and has never lost any of it, then the plant should contain 10 years x 12 months x 10 waterings x 30 µg = 36 mg of K.

If I take the dry mass of a plant to be 5% of its living mass, then the plant tissue analysis should show 36 x 20 = 720 mg/kg or 0.72 mg/g. With K being 0.0391 mg/mmol, then that would be 0.72/0.0391= 18.4 mmol/g dry weight.

How does that compare to the tissue analyses we've discussed? The only one I've grabbed (Marschner) shows sugar beets at 2.54.


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## gonewild (May 23, 2014)

Ray said:


> I agree that there's no need for the rudeness, Adam, but it can still be a fun mental exercise!
> 
> Lance - I have no doubt that ratios are important, but if I may extend your human analogy, a person in a grocery store isn't going to eat everything there.


Good analogy...

No the person wont eat everything in the store.
But the proven fact is that because so much is available the person will eat more than is needed and more than is healthy.
And at the end of the month every single food item has been consumed (including junk food) by all the individual persons foraging in the store.
Now imagine each individual shopper as being equal to a single plant in your greenhouse.
Your collection has consumed far more than needed and consumed food that is not a healthy balance of ratios between nutrients.
As a result some individuals (persons or plants) are extremely healthy and some are dieing from dietary excess.

I have to read the rest of your post a dozen more times but it looks like it has some really good info!


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## Stone (May 24, 2014)

Ray said:


> > Most of my paphs, as I have said before, have gone from 1-, maybe 2 new growths per cycle to 3-, 4-, or 5, and they are getting bigger, faster. I had spikes out the ying-yang a couple of months ago, but mice "helped" me get rid of those...
> 
> 
> 
> ...


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## Stone (May 24, 2014)

gonewild said:


> > In Nature nitrogen becomes available to plants on a constant basis from micro-organisms. It does not only come to the plant when it rains, it is constantly converted and released to plants.
> 
> 
> True but the N is not stolen from the microbes etc., it becomes available from release or leaching or as the microbe dies and this N is also included when measurements are taken
> ...


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## Stone (May 24, 2014)

Rick said:


> > But 2 other points.
> > 1) As Lance points out, between BG algae (in mosses or lichens) or other nitrogen fixing organisms, there is an N pipeline that transcends stemflow.
> 
> 
> ...


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## Stone (May 24, 2014)

AdamD said:


> > After reading this entire thread in one sitting I've scientifically deduced that you all have way too much time on your hands.
> 
> 
> Maybe but its better than sitting in front of the tube getting wasted.
> ...


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## DarioU (May 24, 2014)

NH4 is an antagonist of Ca. How do you consider Ureic N as NH4 N? Is the rate N as Nh4 / N as NO3 really Ureic N + NH4 N / NO3 N?
Thank you to all.


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## Stone (May 24, 2014)

DarioU said:


> NH4 is an antagonist of Ca. How do you consider Ureic N as NH4 N? Is the rate N as Nh4 / N as NO3 really Ureic N + NH4 N / NO3 N?
> Thank you to all.



NH4 is strongly antagonistic to all cations and NO3. Urea is converted to NH4 within a couple of days so you can probably regard it as ammonium. Phal trial by Wang found best growth with 50/50 NO3/NH4 or higher NO3 up to about 75% I think.


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## gonewild (May 24, 2014)

Stone said:


> gonewild said:
> 
> 
> > True but the N is not stolen from the microbes etc., it becomes available from release or leaching or as the microbe dies and this N is also included when measurements are taken
> ...


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## gonewild (May 24, 2014)

Stone said:


> Ray said:
> 
> 
> > Ray, I can think of no possible reason where a reduction in K like this can lead to a doubling or tripling of adventitious growths.(which I would be very happy to acheive by the way!) If you can I would love to consider the process. If as Rick contends, it is from increased Ca or Mg uptake or less antagonism with other elements, I still fail to understand the process.
> ...


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## Ray (May 24, 2014)

Stone said:


> Ray said:
> 
> 
> > Ray, I can think of no possible reason where a reduction in K like this can lead to a doubling or tripling of adventitious growths.(which I would be very happy to acheive by the way!) If you can I would love to consider the process. If as Rick contends, it is from increased Ca or Mg uptake or less antagonism with other elements, I still fail to understand the process.
> ...


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## gonewild (May 24, 2014)

Mike.... in the spirit of discussion....

Once you accept that living micro organisms provide most of the Nitrogen for orchid plants you will begin to understand the "low K theory".
I know you don't accept this but just pretend you do.
Then study the effect of potassium on micro organisms and you will see that certain levels of potassium are lethal (toxic) to many micro organisms.
Does it not make sense that high levels of K will possibly kill the micro organisms growing around and on orchids in a greenhouse?

Without micro organisms to provide nutrients for orchid roots to absorb it becomes necessary to apply heavy doses of liquid fertilizer to make up for the missing organisms.

It may be that potassium excess is not toxic directly to the orchid plants but indirectly it creates a toxic environment. Same result just different way of wording the" low K theory"

Now Google....nitrogen fixing organisms orchids..... and accept that living organisms play a major role in nutrient supply for orchids.

Just in case GooglePeru has different search results than your Google here are a few selected directly related to this topic articles.
(Maybe you can find something in them to prove me wrong)


http://www.dli.gov.in/data_copy/upload/INSA/INSA_2/20005a13_515.pdf

http://aob.oxfordjournals.org/content/48/5/705.abstract

http://www.sciencedirect.com/science/article/pii/S0944501306000942

https://www.uni-jena.de/unijenamedi...o_pharm/allg_bot/ls_plantphys/B_Symbiosis.pdf

http://www.canadianorchidcongress.ca/Ingrid/micro.html

http://www.google.com.pe/url?sa=t&r...zZmtDRb2jgy70zEEQ&sig2=0kq4rP9w-bowYU6b4TFrCQ


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## gonewild (May 24, 2014)

Ray said:


> Stone said:
> 
> 
> > I never claimed it was from the K-Lite - I simply stated that since using K-Lite and KelpMax, that's what I'm seeing. I agree that it is more likely an effect of the KelpMax chemistry, but I don't have any proof that it's either of them, or both.
> ...


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## gonewild (May 24, 2014)

It's cold and raining and I have too much time on my hands so here.....

http://www.falw.vu.nl/nl/Images/11 - heijden_tcm19-29530.pdf

One part.......

Perhaps the most important route by which free-living
microbes influence plant nutrient availability, and hence
plant productivity, is via processes of nutrient mineraliza-
tion, whereby soil microbes break down soluble and
insoluble organic matter and convert it into inorganic, plant
available forms. Most soil N (some 96–98%) is contained in
dead organic matter as complex insoluble polymers such as
proteins, nucleic acids and chitin, and these polymers are
broken down into dissolved organic N (DON) by extra-
cellular enzymes that are produced by soil microbes
(Schimel & Bennett 2004). This DON, which can constitute
a significant portion of the total soluble N pool, is either
absorbed by free-living soil microbes, or it is mineralized by
the microbial biomass (under conditions when microbial
growth is C limited), thereby liberating inorganic-N into the
soil environment. Alternatively, plants might take up DON
directly from soil, in the form of amino acids, thereby
by-passing the microbial mineralization step. This was
shown to be the case in many ecosystems, but especially in
those that are strongly N limited, such as in arctic This growing awareness of the ability
of plants to use organic N and compete with soil microbes
for N has led to a radical rethink of terrestrial N cycling and
especially the processes that control N availability to plants
(Schimel & Bennett 2004)


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## gonewild (May 24, 2014)

and another....
http://omicsonline.org/nutritional-...n-into-plant-nutrients-2157-7471.1000e104.pdf


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## Rick (May 24, 2014)

Stone said:


> NH4 is strongly antagonistic to all cations and NO3. Urea is converted to NH4 within a couple of days so you can probably regard it as ammonium. Phal trial by Wang found best growth with 50/50 NO3/NH4 or higher NO3 up to about 75% I think.




Yes ammonium is antagonistic with all the cations, which MAY be why the Euro growers with high hardness water and high K fert where seeing as good
results with ammonia addition.

You are also correct about the conversion of urea to ammonia.

Ammonia also pushes the pH of the mix down way faster than with nitrate (mainly because of bacterial nitrification)

In general high N (especially with ammonia/urea as the base) just adds a lot of effort in pot management issues that could be avoided by just not fiddling with it.


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## Stone (May 24, 2014)

gonewild said:


> Stone said:
> 
> 
> > > Yes but as I have said several times each plant species have evolved in relationship with certain species of micro organisms.
> ...


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## Stone (May 24, 2014)

gonewild said:


> > It's cold and raining and I have too much time on my hands so here.....
> >
> > http://www.falw.vu.nl/nl/Images/11 - heijden_tcm19-29530.pdf
> >
> ...


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## Stone (May 25, 2014)

Rick said:


> Yes ammonium is antagonistic with all the cations, which MAY be why the Euro growers with high hardness water and high K fert where seeing as good
> results with ammonia addition.
> 
> You are also correct about the conversion of urea to ammonia.
> ...



You're not confusing NH3 with NH4 are you?


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## gonewild (May 25, 2014)

Stone said:


> gonewild said:
> 
> 
> > Stone said:
> ...


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## Rick (May 25, 2014)

Stone said:


> You're not confusing NH3 with NH4 are you?



The state of which is pH dependent. At the pH's ranges we work with in plants (<7.0) we work with 99% (at least) ionized NH4 (but measurement units in the lab are still NH3-N). From a math standpoint for calculation of application the difference is negligible.

Also of note is the high rate at which nitrifying bacteria convert ammonia to nitrate.

So like the case with urea (vs ammonia), only the fluid that immediately hits the roots (or leaves) gets the actual ammonia, while all the rest held in the potting mix gets converted to nitrate (most likely in less than a day in a nice dirty pot). So for the duration between feeding events the plant sees even more nitrate.


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## Rick (May 25, 2014)

Ray said:


> f those "groceries" a plant takes up:
> 
> This morning, I divided a vanda, and had 5 bare-root divisions. I measured their total root lengths, weighed them as-is, immersed them in 80°F water until the velamen was mostly transparent, and weight them again. On average, they weighed 101 g dry, 107 g "saturated", and had an average root length of 70".
> 
> So if I assume 10 waterings per month @ 3 ppm K, plus one at 25 (from the KelpMax), my plants are being exposed to something in the neighborhood of 5 ppm K on average. That 6 g of absorbed liquid, containing 5 ppm K, would carry 30 µg K. If it has absorbed that consistently over it's 10-year life, and has never lost any of it, then the plant should contain 10 years x 12 months x 10 waterings x 30 µg = 36 mg of K.



Ray
I think another component that should be accounted for in total mass balance uptake is direct foliar uptake. This looks to be a significant uptake mechanism in plants that may not need a lot of water to actually be transferred into the plant. This mechanism may also be biased to ammonia potassium and Mg(?)uptake. I also read that K attached to organics is sucked up through leaves more efficiently than as KNO3 (which still seemed pretty decent in a trial with turf grass).

I don't know about most folks, but I spray everything when I water/feed.


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## Catt Mandu (May 25, 2014)

Rick said:


> https://www.msu.edu/~warncke/E0486.pdf
> 
> Michigan State University seems to be pretty comfortable with the concept of K antagonism. Where's their proof or does MSU deal in pseudoscience?
> (note this is a 1994 document, and K antagonism articles go back a lot farther than that)
> ...



Well, I read through the above article above on row crops, and while it does say K, Ca, and Mg should be in balance, and soil pH needs to be above 5 (there's the potential for numerous nutrient deficiencies at pH below 5), I am not seeing anything to support the ultra-low K idea.

So, where does this idea come from, that if you supply more than 10 ppm of K, adding Ca and Mg is a waste of time? Or that potassium will block the Ca and Mg uptake even if you add more Ca, for example?

Since we're talkin' row crops, let's see what the MSU folks recommend for fertilizers: http://fieldcrop.msu.edu/uploads/documents/E2904.pdf
It's a pretty common pattern; most crops, roughly equal N and K2O, much lower P2O5. The same article provides recommendations on Ca and Mg needs.

I have been hearing the low K story for a couple of years, and honestly, I don't see the logic in it. That said, do as you like! But, I do think it is reasonable that when a very specific claim is made (i.e., Ca and Mg supplementation is a waste of time if K supplementation is above 10 ppm), it is very reasonable to ask for some reputable proof (published science).


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## Catt Mandu (May 25, 2014)

Ray said:


> I agree that there's no need for the rudeness, Adam, but it can still be a fun mental exercise!
> 
> Lance - I have no doubt that ratios are important, but if I may extend your human analogy, a person in a grocery store isn't going to eat everything there.
> 
> ...



Ray, a key problem with the above numerical exercise is assuming that the plant has never lost any of the K it has absorbed. This would be like me saying that over the course of 56 years, I have eaten an average of 2 eggs a week, 2 eggs x 52 weeks x 56 years = 5,824 eggs. At 2 ounces each, that's 11,648 ounces of eggs, or 728 pounds. You will just need to take it on faith that I don't weigh 728 pounds, and my mass does not consist entirely of egg. This is, of course, because I periodically "conduct a movement", getting rid of whatever nutrients I've processed, but no longer need.

Your Vanda does this too. Every time it drops a leaf, sheds an old root, jettisons some old plant stem or a spent bloom or flower spike, your Vanda is "debulking". It is well known that this is the manner by which plants get rid of wastes. As such, a calculation such as yours is missing an important "exit" for K to leave the system. There may also be other ways for K to leave the plant (for example, I have no idea if extrafloral nectar, produced by many orchids, contains any K, but it might).


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## Rick (May 25, 2014)

Catt Mandu said:


> So, where does this idea come from, that if you supply more than 10 ppm of K, adding Ca and Mg is a waste of time? Or that potassium will block the Ca and Mg uptake even if you add more Ca, for example?



The 10 ppm threshold is extrapolated from the work of Poole and Seeley (Cornell U. published back in 1978)

With a constant background of 200ppm Ca, applications of as low as 50 ppm K (in Cattleya and Cymbidium) and 100 ppm K (Phalaenopsis) were able to reduce Ca in leaf tissue. Progressive increase of K dose continued to decrease the Ca concentration in leaf tissue. As these were the lowest K doses tested, I had to extrapolate to get to a point where Ca was not antagonized as per insitu leaf tissue concentration values.

As far back as the Poole and Seeley paper was written, they recognized the phenomena as already well documented, and they reference work from 1954.

There's also documentation of this phenomenon by the Potash Institute.


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## ALToronto (May 26, 2014)

Rick said:


> The 10 ppm threshold is extrapolated from the work of Poole and Seeley (Cornell U. published back in 1978)
> 
> With a constant background of 200ppm Ca, applications of as low as 50 ppm K (in Cattleya and Cymbidium) and 100 ppm K (Phalaenopsis) were able to reduce Ca in leaf tissue. Progressive increase of K dose continued to decrease the Ca concentration in leaf tissue. As these were the lowest K doses tested, I had to extrapolate to get to a point where Ca was not antagonized as per insitu leaf tissue concentration values.
> 
> ...



So was this an extrapolation based on a mathematical model (usually some exponential relationship) or a simple straight line? Straight line would be most certainly wrong, and even a model well fitted to relatively high K experimental data would have a very large confidence interval at a point so far removed from the sample space. 

Most often when scientists have to hold their noses and do statistics, they use the lognormal distribution to model data - the most overused statistical distribution, very easy to fit, and very inaccurate at either tail. I would not take an extrapolated value too seriously.


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## DavidCampen (May 26, 2014)

Rick said:


> The 10 ppm threshold is extrapolated from the work of Poole and Seeley (Cornell U. published back in 1978)
> 
> With a constant background of 200ppm Ca, applications of as low as 50 ppm K (in Cattleya and Cymbidium) and 100 ppm K (Phalaenopsis) were able to reduce Ca in leaf tissue. Progressive increase of K dose continued to decrease the Ca concentration in leaf tissue. As these were the lowest K doses tested, I had to extrapolate to get to a point where Ca was not antagonized as per insitu leaf tissue concentration values.



When you reference a paper it is generally considered to be proper to supply enough information so that another person can easily locate the paper.
Is this the Poole and Seeley paper you are referencing:
http://www.firetailorchids.com.au/_pdfs/poole_and_seeley.pdf

That paper does not support any of the claims you made above.




Rick said:


> There's also documentation of this phenomenon by the Potash Institute.


Again, with no reference to the actual document this statement is worthless. Most likely is that it does not support your claims.


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## Catt Mandu (May 26, 2014)

Rick said:


> The 10 ppm threshold is extrapolated from the work of Poole and Seeley (Cornell U. published back in 1978)
> 
> With a constant background of 200ppm Ca, applications of as low as 50 ppm K (in Cattleya and Cymbidium) and 100 ppm K (Phalaenopsis) were able to reduce Ca in leaf tissue. Progressive increase of K dose continued to decrease the Ca concentration in leaf tissue. As these were the lowest K doses tested, I had to extrapolate to get to a point where Ca was not antagonized as per insitu leaf tissue concentration values.
> 
> [snip by Catt Mandu here]



I'm assuming the reference supplied by David is the Poole and Seeley paper that you were referring to (BTW, thanks David). If not, please provide the reference.

So, using the same kind of logic, and doing the same type of extrapolation, would you conclude from Poole and Seeley's Table 2 that nitrogen is antagonizing all of the other plant macronutrients in Cattleya and Phalaenopsis? Is the conclusion that we should stop providing N because it is causing deficiencies in the other macronutrients? IMO, clearly not. Nor is the data indicating that if you provide more of the other macronutrients, the plants will not respond to the nutrient increase.

Note also in Table 2 the leaf concentrations of K relative to N and P. K is consistently the higher of the three nutrients in the leaves (percentages in the order K > N > P). 

What makes the most sense, IMO, is to provide nutrients in roughly balanced proportions to plant requirements. If you provide adequate supplies of N, P, K, Ca, Mg, and S, the plant will sort out what it needs. Add in the micronutrients if you are using a mineral-deficient water source. Also, adjust pH so that plants can utilize the nutrients you are providing.


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## Rick (May 26, 2014)

ALToronto said:


> So was this an extrapolation based on a mathematical model (usually some exponential relationship) or a simple straight line? Straight line would be most certainly wrong, and even a model well fitted to relatively high K experimental data would have a very large confidence interval at a point so far removed from the sample space.



No not completely based on math (and correct its not linear), but also considering insitu data. I have not found any literature indicating that solutes in the orchid environment are greater than ~10ppm. Generally less than 5 ppm.

Has anyone else located data indicating that orchids get applications of NPK at K concentrations >50ppm or even 25ppm?


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## Rick (May 26, 2014)

Catt Mandu said:


> I
> Note also in Table 2 the leaf concentrations of K relative to N and P. K is consistently the higher of the three nutrients in the leaves (percentages in the order K > N > P).



Also note Table 3 when N was held constant and only K manipulated.


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## gonewild (May 26, 2014)

Rick said:


> Has anyone else located data indicating that orchids get applications of NPK at K concentrations >50ppm or even 25ppm?



I have some personally collected data I'll post later today or tonight that will help answer that question.


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## Ray (May 26, 2014)

Catt Mandu - I agree 100% that there are losses (you should see my greenhouse floor every spring!). My point with the math was to show the very low amounts that we are applying.

We have done a lot of discussion of fertilizer concentrations and ratios, but very little in terms of mass actually absorbed by the plant. I was merely trying to bring that into the discussion, even with a great many "outrageous" assumptions.


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## Rick (May 26, 2014)

Catt Mandu said:


> What makes the most sense, IMO, is to provide nutrients in roughly balanced proportions to plant requirements. If you provide adequate supplies of N, P, K, Ca, Mg, and S, the plant will sort out what it needs. Add in the micronutrients if you are using a mineral-deficient water source. Also, adjust pH so that plants can utilize the nutrients you are providing.



That certainly is the mainstream hobby practice that I followed for years and got mainstream hobby results (which for me were merely adequate and limiting).

Dario is certainly free to stay within mainstream practices and should expect at least that level of satisfaction.


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## Rick (May 26, 2014)

Catt Mandu said:


> What makes the most sense, IMO, is to provide nutrients in roughly balanced proportions to plant requirements. If you provide adequate supplies of N, P, K, Ca, Mg, and S, the plant will sort out what it needs. Add in the micronutrients if you are using a mineral-deficient water source. Also, adjust pH so that plants can utilize the nutrients you are providing.



What are the plant requirements you are referring too?

Are you refering to sufficiency standards and if so which ones?


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## cnycharles (May 26, 2014)

You mention that the 'plant will sort out what it needs', but some elements/compounds it takes it up whether it needs it or not, and then it has to deal with the excess. Previous multiple discussions about this point have already been hashed over here


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## Stone (May 27, 2014)

cnycharles said:


> You mention that the 'plant will sort out what it needs', but some elements/compounds it takes it up whether it needs it or not, and then it has to deal with the excess. Previous multiple discussions about this point have already been hashed over here



This is not a problem when you apply at the correct ratio and concentration.
Basically, plant growth is reduced when the first of any element becomes too high in concentration and it is also reduced when the first of any element becomes too low in constentration. Therefore the trick is to apply the elements at optimum or just below optimum to achieve the best performance. And this is where all the trouble starts :evil:


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## Stone (May 27, 2014)

Catt Mandu said:


> > Your Vanda does this too. Every time it drops a leaf, sheds an old root, jettisons some old plant stem or a spent bloom or flower spike, your Vanda is "debulking". It is well known that this is the manner by which plants get rid of wastes. As such, a calculation such as yours is missing an important "exit" for K to leave the system. There may also be other ways for K to leave the plant (for example, I have no idea if extrafloral nectar, produced by many orchids, contains any K, but it might).
> 
> 
> 
> ...


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## Ray (May 27, 2014)

Stone said:


> Therefore the trick is to apply the elements at optimum or just below optimum to achieve the best performance. And this is where all the trouble starts :evil:


Ah yes, the "holy grail" or horticulture.

Nobody really knows what the "optimum" is for any plant, including major food crops like corn, and certainly not orchids. You apply something, observe the "performance" of the plant, then do tissue analysis to try to correlate them.


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## Rick (May 27, 2014)

Stone said:


> Yes. And another major way K is removed is through leaching. Every time you hose down your plant K is removed more than most other elements.
> You can imagine how much is leached during 5 days of constant heavy rain but of course there must also be a balance between uptake and renoval.
> But we don't really leach anything like a monsoon therefore K might not be as necessary in cultivation. That's one for Rick....Oh no!!!



Mike that doesn't make any sense. Epiphytic plants should have no K at all in them during the rainy season in that case, and that just completely negates all your argument that epiphytes get their K from stemflow and throughfall.

Leaching out of dead plant materia is something else altogether agreed.

Also with reference to loss of K from leaf drop, the Zotz work on Panamanian epiphytes showed readsorption of K from old leaves (before leaf drop) was somehere around 30-50%. P was recycled at roughly 60% while Ca and Mg where hardly recycled at all.


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## gonewild (May 27, 2014)

Rick said:


> Has anyone else located data indicating that orchids get applications of NPK at K concentrations >50ppm or even 25ppm?



I have made a lot of insitu tests now here in the Peruvian orchid zone.
I am not making chemical analysis to determine ratios of mineral rather taking simple ppm/ec and pH. But I am sampling actual water around the orchid root zone.

The below tests will give a direct clue about the quoted question. 

Sample#1
Rainwater
ppm 0.0
pH 7.0

Sample#2
I collected moss samples from three separate but similar trees. Moss was taken directly from areas with orchid roots growing in on or through it. Many different orchid species are present including also ferns, pepperomias, and assorted other plants.
The samples were collected during a light rainfall in the "dry" season.
The moss was saturated and flowing with rain water that would represent "stem flow". I placed the samples directly into a plastic bag and allowed the water to drain off and tested this sample.

Free drained water was clear:

ppm 14.7
pH 6.6

I then squeezed the moss to collect all water possible:
Squeezed water was moss green color.

ppm 102.0
pH 5.9

Sample #3
Walking through a virgin forest at 1200m elevation I took equal moss samples from 50 different trees each sample was taken from a position the would receive the most influence from stem flow.

Free drained water was clear:
ppm 13.9
pH 6.2

I added just enough water to slightly over saturate the moss (after it had been drained. Soaked for 24 hours and squeezed to collect a sample.

ppm 119.0
pH 5.5

Sample#4
This sample is a random collection containing of orchid roots, moss, bark fragments and Lichens. All collected from the root zone of orchids.
This sample contained enough water that I made the sample by lightly squeezing the mass.

Water was slightly not clear:
ppm 108
pH 5.7

Sample#5 

Stem flow water:
Collected from bark and leaves with very little moss or Lichen present.
This might represent a mid point between stem flow and through fall.

ppm 6.7
pH 6.9

Sample#6
Organic matter collected from tree crotch growing orchids:
Sample saturated with rainwater and allowed to stand 24 hours. 

ppm 44
pH 4.8


Sample#7
Limestone rock face.
Water flowing over bare limestone, moss, ferns, begonias, aroids and through trailing tree roots. This water represents a Limestone formation.

ppm 8
pH 5.2 (yes that is correct)


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## Rick (May 27, 2014)

And this is TDS (all salts) and not just K.


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## Rick (May 27, 2014)

Stone said:


> You can imagine how much is leached during 5 days of constant heavy rain but of course there must also be a balance between uptake and renoval.
> But we don't really leach anything like a monsoon therefore K might not be as necessary in cultivation.



If leaching from live plants was significant it would end up downstream in creeks/rivers. The amount of K in creeks/rivers is generally down <5ppm

I managed to locate water chem data for creeks/streams in the karst areas of PNG where the giant bulbophyllum species are found (like under the waterfalls/caves/overhangs). Surface water K is down in low single digit ppms (just about like any karst derived river in the world).

Sadly this data came from an EIS conducted for petroleum industries looking to exploit the areas where these orchids come from.


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## Stone (May 28, 2014)

Rick said:


> > Mike that doesn't make any sense. Epiphytic plants should have no K at all in them during the rainy season in that case, and that just completely negates all your argument that epiphytes get their K from stemflow and throughfall.
> 
> 
> 
> ...


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## Bjorn (May 28, 2014)

I have read this thread with great interest, but to me -except for Lances last post - there are three groups that have their predetermined opinion and that try to knock down the opponents using whatever arguments that are available.
Rick and Lance firmly belive in low K, Mike (Stone) cannot accept the good results of Rick because orchids grow perfectly well with normal K-Levels, and then you have David and Catt Mandu that seems more hooked up on the formal deficiencies, as if we were writing scientific papers here.
Ok what has been the outcome of the discussion? In my opinion, anecdotal evidence (and that is good enough for me) has shown that orchids can be grown with low K, but it may not be necessary. There are strong evidence that they suffice with some 100ppm TDS in their water as well.
Orchid roots absorb cations in their velamen (might be so for paphs as well) so nutrition is highly dependent on the balance of nutrients and not so much on the concentration. Actually they do fine with very dilute fertilisers. If the balance is wrong, over time, malnutrition hits in ; much like people getting unhealthy from obsessive sugar intake (thik Rick used that one some time(years) ago). So, continous fertilising with very diluted fertiliser is one clue here.
Possibly, reduced potassium is a good thing as well. Many people use urea or ammonium based fertilisers and the kationic nature of these (NH4+) perfectly fits into the "active sites theory" of the velamen. Nitrate does not btw.
One thing that everyone except Xavier seems to ignore are the micronutrients.
Xavier (Roth) has repeatedly written that the Fe:Mn:Zn balance normally is more or less opposite to the chemistry of wild-grown leaves. You may find more on that in Xaviers thread on "Mineral Nutrition".
The reason why I mention this is that I noticed a growth spurt on my randsii seedlings once I sprayed with Dithane which is basically a manganese-zinc compound. Suddenly they started growing at the speed of normal paphs!
Might be a coincidence? Well that triggered me to look a bit further into this. Some of you may have noticed that many of my plants grow rather quickly. In hindsight, one of the variables in my growing has been that I have been using a rather special foliar feed as part of my fertiliser regime. This had been mixed 50:50 with K-lite. I did that because of yellowing with K-lite alone and so I thought that I needed Urea (which was 50% of the foliar feed). Checking up things revealed that the urea was not the only difference, the balance in the micros was also totally different. K-lite has Fe:Mn:Zn of 0.115%:0.077%:0.077% (approx 3:2:2)
while this foliar feed had Fe:Mn:Zn of 0.02%:0.26%:0.14% (approx 1:13:7)
Not only the balance, but also the levels were quite different.
And more in line with Xaviers findings on tissue analyses.
The 50:50mix produces a fe:Mn:Zn of 0.0675%:0.1685:0.1085% or roughly 2:5:3 balance.
Note that I have used less Fe and more Mn and significantly more Zn than I would with K-lite alone at a given TDS.
Sorry for the long post, though it was about time to share


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## Stone (May 28, 2014)

Rick said:


> > If leaching from live plants was significant it would end up downstream in creeks/rivers. The amount of K in creeks/rivers is generally down <5ppm
> 
> 
> 
> Perhaps but this data is only relevent to me if you provide the ppm for total N, P, Ca, and Mg as well and preferably from a place where orchids grow.


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## Stone (May 28, 2014)

gonewild said:


> I have made a lot of insitu tests now here in the Peruvian orchid zone.
> I am not making chemical analysis to determine ratios of mineral rather taking simple ppm/ec and pH. But I am sampling actual water around the orchid root zone.
> 
> The below tests will give a direct clue about the quoted question.
> ...



All very interesting Lance and thank you. However it tells me nothing about what and how I should feed my orchids. Only that they get low concentrations of everything which we already knew.


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## Stone (May 28, 2014)

Bjorn said:


> > Mike (Stone) cannot accept the good results of Rick because orchids grow perfectly well with normal K-Levels
> >
> > That is not accurate Bjorn. I have acknowleged that Rick's plants (the paphs in baskets which I have seen are doing well and in some cases very well)
> >
> > ...


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## Stone (May 28, 2014)

Bjorn said:


> .
> 
> 
> > One thing that everyone except Xavier seems to ignore are the micronutrients.
> ...


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## Bjorn (May 28, 2014)

Agree Mike, what you give is not necessarily what is consumed. In most cases the bulk of the fertiliser drops directly onto the floor.
If we accept the suggestion that the velamen of the orchid roots contain active sites that captures the nutrients of the water coming (Zotz and Winkler, Oecologia (2013) 171:733–741), then the proportions must have significance for the uptake. Then, if the sites get occupied by e.g. Fe it will be on the expense of other, more needed nutrients. 
A too high amount of the wrong ion may thereby block uptake of other essential nutrients.


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## Ray (May 28, 2014)

One thing that really urinates me (pisses me off) about Bjorn's post is his apparent inability to break his comments into readable paragraphs!

That aside - what makes you think the nitrate ion is not trapped by the velamen?


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## Bjorn (May 28, 2014)

See what you mean Ray; hardly readable right? I'll try to improve.
Below I put up some more speculative assumptions trying to explain a bit how and why

Then your question about nitrate; no proof for this, but most nutrients are cations (positively charged), and I just assume that the bonding mechanism in the velamen is of electrostatic nature. E.g. many ceramic raw materials have negative surface charges.(negative zeta-potential although not exactly the same) Cellulose is another material that normally is negatively charged, and that may be more relevant in this context.

To grab kations by electrostatic attraction, negatively charged sites must be present, so unless you have special (=positively charged) sites for anions (which might be present of course) they will not get electrostatically attracted. 

Another thing is that to be used by the plant for aminoacid production (aidied by nitrate and nitrite reductase) the nitrate has to be reduced, whilst ammonium is already in the reduced state and should therefore be readily available.


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## Ray (May 28, 2014)

OK, but an NO3 ion is negatively charged....


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## Rick (May 28, 2014)

Stone said:


> I have acknowleged that Rick's plants (the paphs in baskets which I have seen are doing well and in some cases very well)



I'm hurt Mike

Didn't you like my Maxilaria tenufolium

That's in a pot

And SlipperKing has been garnering a lot of awards with his plants (mostly in pots) since going low K.

Emydura has his own version of low K which seems to be producing some amazing results.

I don't think its the baskets for anything other than it reduces the overall exposure to fertilizer (like a mounted plant).

But my mounted plants have also improved. (Didn't you like my Phalae pallens?)


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## Rick (May 28, 2014)

Bjorn said:


> One thing that everyone except Xavier seems to ignore are the micronutrients.
> Xavier (Roth) has repeatedly written that the Fe:Mn:Zn balance normally is more or less opposite to the chemistry of wild-grown leaves. You may find more on that in Xaviers thread on "Mineral Nutrition".
> The reason why I mention this is that I noticed a growth spurt on my randsii seedlings once I sprayed with Dithane which is basically a manganese-zinc compound. Suddenly they started growing at the speed of normal paphs!



I haven't totally ignored the micros Bjorn, and this may get everybody all inflamed again, but K is antagonistic to Zn (probably just about all cations besides Ca and Mg).

So after taking the K out of the equation, I've been waiting for the last few years to see if other issues maybe related to micros will pop up. Not for me yet though.


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## Stone (May 28, 2014)

Rick said:


> I'm hurt Mike
> 
> Didn't you like my Maxilaria tenufolium
> 
> ...



Didn't mean to hurt Rick!
What sticks in my mind more than any other was the the mastersianum and the delenatii. I can't remember all the plants you are posting but I am willing to take your word that they are all thriving. But it is very hard to compare yours with a thousand others and say this or that is doing better.
I also have lots of plants which I'm pretty proud of and which have won cultural certificates and have all been fed quite heavily with K. I wonder if with paphs at least, feeding very low consentrations is more important than worrying too much about the potassium ratio.


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## Rick (May 28, 2014)

Stone said:


> That there are countless examples of these orchids doing equally well with K concentrations as high as the N given to them.



However, from the countless complaints I see on this forum the old traditional fert applications aren't cutting it. (or orchid growers are perpetual whiners). Your countless examples really seem to be in the minority.
Then when an alternative to the system is suggested then everyone is in denial of their complaints:sob: And we start dragging out those pics of the one plant (out of 100) that turned into that awesome specimen plant that got the CCE (forgetting the pile we just put into the compost heap).


The traditional agri food crop application methods produce orchids that emulate expectations for food crops. Lots of production in short time frames requiring lots of labor and material effort followed by trash can. I would guess that the bulk of orchid growers are just fine with that, and are encouraged to be fine with that attitude. Hybrid Phalaes have replaced poinsettia as the ultimate throw away plant. 

And the agri science folk pace nutrient load based on soil deficiencies and plant age. The orchid hobbyists modus operandi is to apply the kitchen sink in mass quantities regardless of the age of plant and then scratch there heads wondering how the corn farmers do it so easily?

I responded to complaints and perceived inadequacies in my growing by breaking out of the "how everyone else does it" system and looked for a common solution, instead of the myriad of excuses and grasping at minutia that orchid growers seem to get fixated on.

And so far its still working


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## Stone (May 29, 2014)

Rick said:


> > However, from the countless complaints I see on this forum the old traditional fert applications aren't cutting it.
> 
> 
> 
> ...


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## DarioU (May 31, 2014)

Perhaps I tend to simplify but if the problem would be that K blocks the uptake of Ca and Mg could we superate the problem giving these elements not mixed in the same time? One time NPK fert and an other day Ca/Mg fert.


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## Rick (May 31, 2014)

DarioU

It depends on the type of potting mix, the frequency and amount of application, and the concentration applied.

High Cation Exchange of various potting mixes will hold up K rather than Ca/Mg. It's not just a basic sponge effect, but a chemical bias. And once its in the mix it takes a high dose of Ca or Mg to knock it back out. What you suggest probably is happening for lots of growers when they fertilize with NPK infrequently and water frequently with are regular city or well water that has plenty of Ca/Mg in it already. 

Orchiata bark prides itself on having a low CEC so it holds up less K over repeated fert applications. You might have seen reference to Xavier who supplied data to this site showing that Orchiata holds up less than 1/2 the potassium compared to coconut coir and sphagnum moss.

Lots of folk are having good results using Orchiata bark (which was lime composted). You probably don't need to add any separate Ca/Mg using this material and if you mix your standard NPK fert in diluted city/well water you will also get a lot of Ca Mg without having to add it in from separate components.

Do you have a water report for your drinking water?

You mentioned high sodium, but it is rare that well waters are higher in Na than Ca unless they have been run through a water softening system.

I also have well water that has very high EC but it is all salts of Ca/Mg with low Na. I dilute it 10 or 20:1 to add Ca/Mg


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## DarioU (May 31, 2014)

Thank you Rick. My well water (not tap water) has 68 ppm Ca, 21,9 ppm of Mg and 36,2 ppm of Na. Because I have read that Na has to be lower then 10 ppm and better lower then 5 ppm I diluite Well Water/RO water 1:4.
What do you think about it?
Dario


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## Rick (May 31, 2014)

http://cpl.usu.edu/files/publications/factsheet/pub__9468201.pdf

DarioU this kind of goes back to your original question.

addition of gypsum didn't help out with the high K coir


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## Stone (Jun 1, 2014)

Rick said:


> > > the old traditional fert applications aren't cutting it
> >
> >
> >
> > ...


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## Rick (Jun 1, 2014)

Stone said:


> Rick, Can I remind you of the magnificent example of P. bellatulum posted by e-spice a while back. One of the best and healthiest I've ever seen and one we all aspire to I would think!



Well that's one blast from the past Mike, so now show me where that plant became just one of the "vast majority" of bellatulum out their in culture. I also grew a bellatulum to that size with MSU. Repotting every 6 months, loosing all the roots/regrowing roots, bag n'sphag, adding oyster shell, ...... when it got up to 8-10+ growths it started producing stunted growths (though still blooming). I switched it over to SH as per ESpices example, it frittered away to nothing. I went through a whole compot of seedlings from a selfing of this plant. All 25 are gone after trying all the usual ascribed methods and materials (including SH). None even made it to a first blooming. The common thread was MSU at 100ppm N weekly.

So why didn't MSU SH work for my bellatulum? I truly tried to apply what I learned from Espices fantastic plant.

Why isn't every GH filled with monster pots of bellatulum when literally thousands of seedlings are sold each year?

Espices awesome plant was something we all aspired to because no one else was achieving that result. It wasn't in the "vast majority" of bellatulum in culture.

That was also a few years ago, so it would be good to get an update on that plant.

I've also had lots of big, impressive, enviable plants grown on MSU at high feed rates that are no longer around. I'm not saying it can't be done, I'm saying its not worth the effort and loss to get there. In developing the low K system I was primarily responding to all the complaints of species that "cannot be grown in artificial culture". I didn't suspect it would make such a difference for all my easy stuff.


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## Rick (Jun 1, 2014)

Stone said:


> Rick, Can I remind you of the magnificent example of P. bellatulum posted by e-spice a while back. One of the best and healthiest I've ever seen and one we all aspire to I would think!
> The fertilizer used. MSU...and from memory MSU has a very high K/N ratio.
> Ouote " I use a very dilute MSU (from Ray's) and some Mg now and then''. (It was grown in semi hydro)



http://www.slippertalk.com/forum/showthread.php?t=13111

Interesting history from 2009. 

I can't recall how "very dilute MSU" was for E-spice at that time (could have been down to around 10-20ppm N and therefore K around the same concentration", but apparently that didn't translate to success for barbata types.

Also note that in 2009 Ray was pretty happy with MSU at 125ppm N (~135ppmK), but got happier with K lite at 35ppm N (~3.5ppm K) in 2012/2013.


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## DavidCampen (Jun 1, 2014)

Rick said:


> http://cpl.usu.edu/files/publications/factsheet/pub__9468201.pdf
> 
> *addition of gypsum didn't help out with the high K coir*



Because the potassium content of the coir was not causing a calcium deficiency. The authors state that they were unable to determine the cause of poor growth in coir. The only take away from this article is to not use coir. The article says nothing that supports your potassium toxicity conjecture.

In the introduction of the article there is mention of another publication that claimed that high potassium content of coir available in Australia required the addition of gypsum to increase calcium uptake but the experimental data in the article does not support this.


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## Stone (Jun 1, 2014)

Rick said:


> .
> 
> 
> > I also grew a bellatulum to that size with MSU. Repotting every 6 months
> ...


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## Stone (Jun 1, 2014)

Rick said:


> > I can't recall how "very dilute MSU" was for E-spice at that time (could have been down to around 10-20ppm N and therefore K around the same concentration", but apparently that didn't translate to success for barbata types.
> 
> 
> 
> Not sure what concentration was used. I'm finding it easier to grow my brachy seedlings than barbatas. Why I still don't know. Possibly a humidity issue? But I would suspect that barbatas coming from a more ''leafy'' and dense forested habitat may have more K available to them than something from a limestone cliff?


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## Rick (Jun 3, 2014)

DavidCampen said:


> Because the potassium content of the coir was not causing a calcium deficiency. The authors state that they were unable to determine the cause of poor growth in coir. The only take away from this article is to not use coir. The article says nothing that supports your potassium toxicity conjecture.
> 
> In the introduction of the article there is mention of another publication that claimed that high potassium content of coir available in Australia required the addition of gypsum to increase calcium uptake but the experimental data in the article does not support this.



I didn't claim that this article supported the position that potassium blocks K, just that adding Ca did nothing to increase Ca in the plants.


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## Rick (Jun 3, 2014)

DavidCampen said:


> Because the potassium content of the coir was not causing a calcium deficiency. The authors state that they were unable to determine the cause of poor growth in coir. The only take away from this article is to not use coir. The article says nothing that supports your potassium toxicity conjecture.




The GrowCoir did really good compared to the Peat control.

The sufficiency standards for corn from MSU indicate leaf K should be between 1.6 -2.5% and Ca 0.2-0.8%

The Tropic grow coir ended up with 3.7% K and 0.3% Ca (regardless of Ca added to the pot). By MSU standards that plant wouldn't be experiencing Ca deficiency, but outright K toxicity (MSU's words not mine). I would acknowledge that some trace nutrients are also elevated, but I don't have the sufficiency standards handy for them. I guess you can blame the poor results on toxicity of those metals if you don't agree with the K sufficiency standards established for corn. 

The GrowCoir corn did great (regardless of Ca added to pot). Those plants ended up with only 1.79% K and and 0.28 Ca. Both values within published sufficiency standards and healthy looking plants to corroborate.

Another take home point from the article would also appear that adding Ca doesn't reduce K in leaves.


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## Rick (Jun 3, 2014)

DarioU said:


> Thank you Rick. My well water (not tap water) has 68 ppm Ca, 21,9 ppm of Mg and 36,2 ppm of Na. Because I have read that Na has to be lower then 10 ppm and better lower then 5 ppm I diluite Well Water/RO water 1:4.
> What do you think about it?
> Dario




That works for me Dario

Do you have the other major ions ( sulfate, chloride, bicarbonate and potassium) values for your well water?


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## DarioU (Jun 4, 2014)

Cl 60,1 mg/l; SO4 61,6 mg/l; K 0,8 mg/l; Zn 12,3 microgr/l; Mn 52,2 microgr/l; Durezza 26 F°; EC 442 microSiemens/cm.
My well water works diluite 1:4 in RO water or without any diluition?
Na is not too hight? 
In the web site of St. Augustine Orchid Society I have read that Na must be lower then 10 ppm.
Thank you
Dario


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## gonewild (Jun 4, 2014)

Stone said:


> All very interesting Lance and thank you. However it tells me nothing about what and how I should feed my orchids. Only that they get low concentrations of everything which we already knew.



You don't see that the nutrients are not moving through the moss in stem flow?

Based on my sample tests it is obvious that the majority of nutrients are supplied by organisms within the root zone and not rain water or atmospheric dust particles.

It tells me a lot about what you should feed your orchids.
The concentrations are not that low in reality and only dissolved salts are measured. But clearly there is not much potassium flowing freely from the canopy as you maintain.

Potassium probably has a toxic effect on all the micro organisms within the root zone. Applying fertilizer levels with K above the toxicity level for the nutrient providing organisms will throw the entire nutrient supply out of balance. The more toxic you keep your growing media the more nutrients you have to apply and the more you take the nutrient supply away from a correct ratio of balance.

How this pertains to the Ca/Mg availability I have no idea but it does seem to have a big effect. It's time for Horticulture to realize that plants don't only utilize NPKCaMgFe from dissolved free flowing salts. The velum of the orchid root should be alive with LIVING nutrient producing micro organisms providing nutrients in many chemical forms such as amino acids and compounds not detected. Does potassium kill these organisms?
K-lite indicates it does (at least to me it does).

I just returned from several days up in the cloud forest, plenty of clouds but zero water fell from the sky, not as rain or fog. But the moss and orchid roots are wet with local moisture and the plants are growing. Growing from nutrients supplied by the living moss/lichen fauna.


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## Stone (Jun 4, 2014)

gonewild said:


> You don't see that the nutrients are not moving through the moss in stem flow?
> To me all the your samples represent ''free'' nutrients.


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## Trithor (Jun 5, 2014)

What happened to the Ca/Mg question answer? How did it get back to K again, surely K is not the center of orchid culture, I understand that it is important and obviously somewhat controversial, but surely the other macro/micros are also important? 
I think we need to organize a conference on K relating to paph culture, I will bring the beer and wine


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## gonewild (Jun 5, 2014)

Trithor said:


> What happened to the Ca/Mg question answer?



I think it was answered early in the thread and then the answer was argued about.



> I think we need to organize a conference on K relating to paph culture, I will bring the beer and wine



I agree, let's meet at my house. :clap:


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## gonewild (Jun 5, 2014)

In case the original question answer was lost in the K debut.....



DarioU said:


> Can I supplement Ca and Mg only with Ca nitrate and Mg nitrate for a long time ?



Yes



> Can I mix in the same solution, in the right doses of course, Ca nitrate and Mg nitrate?



Yes


> Because both (Ca and Mg) are in their nitrate form perhaps I can mix them, I think.



Yes 



> Can add Ca nitrate and Mg nitrate in Fertilizing solution or I must keep them separate?



Can not mix with phosphate fertilizers in concentrate solutions.
Can mix together in dilute fertilizer solutions.



> If I mix them with the fertilizing solution the P precipitate them resulting in P, Ca and Mg deficience?



Yes


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## Stone (Jun 5, 2014)

Trithor said:


> > I think we need to organize a conference on K relating to paph culture
> 
> 
> 
> I don't think paphs will turn out to be very different to any other orchid from nutrient-poor environments. And I assume that the nutrients available to all of them are (for our purposes) the same.


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## Stone (Jun 5, 2014)

gonewild said:


> > I think it was answered early in the thread and then the answer was argued about.
> 
> 
> 
> ...


----------



## gonewild (Jun 5, 2014)

Stone said:


> Trithor said:
> 
> 
> > I don't think paphs will turn out to be very different to any other orchid from nutrient-poor environments. And I assume that the nutrients available to all of them are (for our purposes) the same.
> ...


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## SlipperFan (Jun 5, 2014)

Orchids had better adapt to our culture, or they die! (I know this all too well!)


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## Stone (Jun 5, 2014)

gonewild said:


> Stone said:
> 
> 
> > > To make that assumption is a mistake. A big part of what causes speciation is differences is adaptation to different nutrient supplies. Each species has a different nutrient requirement. We just don't know what the requirements are so we lump them all together and treat them the same. But that does not make it correct.
> ...


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## Ray (Jun 5, 2014)

SlipperFan said:


> Orchids had better adapt to our culture, or they die! (I know this all too well!)



That's my philosophy!


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## gonewild (Jun 5, 2014)

Stone said:


> gonewild said:
> 
> 
> > What was argued was Rick's claim that if K is given at higher than 10ppm, addition of Ca and Mg is a ''waste of time''. Obviously an inaccurate statement. I think this whole debate has probably been worthwhile because if nothing else it has made some of us take a much closer look at orchid nutrition. However I believe claims such as the one above should not go unchallenged. Don't you Lance?
> ...


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## gonewild (Jun 5, 2014)

SlipperFan said:


> Orchids had better adapt to our culture, or they die! (I know this all too well!)



oke:
Would it not be better to adapt our culture to their needs?
(So they will live)

Orchids and plants are kept as pets and deserve at least the same respect as a dog. :sob:


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## gonewild (Jun 5, 2014)

Stone said:


> gonewild said:
> 
> 
> > Stone said:
> ...


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## Stone (Jun 5, 2014)

gonewild said:


> > Recognize that there is a huge amount of unpublished knowledge about plant nutrition that is not available to the general public via the internet.
> >
> > But yes challenge is appropriate....if you are correct....which you are not.
> > :wink:
> ...


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## gonewild (Jun 5, 2014)

Stone said:


> gonewild said:
> 
> 
> > I'ts obviously pointless to continue
> ...


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## Stone (Jun 6, 2014)

gonewild said:


> Stone said:
> 
> 
> > Finally you get the point.
> ...


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## gonewild (Jun 6, 2014)

Stone said:


> gonewild said:
> 
> 
> > We are forever greatful for having been removed from the dark potting shed and shown the lichen encrusted grail of truth.
> ...


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## Stone (Jun 6, 2014)

gonewild said:


> Stone said:
> 
> 
> > Hmmm, and I thought you might have a tiny speck of knowledge that would prove me wrong. But alas, no speck.
> ...


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## SlipperFan (Jun 6, 2014)

gonewild said:


> oke:
> Would it not be better to adapt our culture to their needs?
> (So they will live)
> 
> Orchids and plants are kept as pets and deserve at least the same respect as a dog. :sob:



Seriously, though, I cannot provide a cliff with constantly running water for my Phrags, or always the optimum natural temperatures for all my Paphs. I do the best I can, and hope they can adapt to what I can provide them. All this discussion/argument about nutrients doesn't give all the different orchids I have any more hope of survival than what is the best I can do. 

But have at it!


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## gonewild (Jun 6, 2014)

Stone said:


> gonewild said:
> 
> 
> > Well lets look at your claims then.
> ...


----------



## gonewild (Jun 6, 2014)

SlipperFan said:


> Seriously, though, I cannot provide a cliff with constantly running water for my Phrags, or always the optimum natural temperatures for all my Paphs. I do the best I can, and hope they can adapt to what I can provide them. All this discussion/argument about nutrients doesn't give all the different orchids I have any more hope of survival than what is the best I can do.
> 
> But have at it!



:sob:
You hit the nail on the head. Because an orchid collection has so many different species and each has it's own unique needs there is no way to satisfy all.
Since you can't provide a cliff with running water you need to find the best substitute. Finding the best average nutrient level that should satisfy the majority of the species should be easy. But it requires trial and error. 

All current orchid fertilizers are based on old basic knowledge about plant nutrition. Nothing has really changed in 40 years except the labels and addition of "new" formulas that promise faster, bigger, better growth. Almost all are only based on companies marketing targets and not based on what grows better plants. The K-lite low K fertilizer is the only drastic new formula and it is not based on market need or just something to fill a new package shape. No one involved with the creation of it is going to make a profit from it. It is not based on research done by a fertilizer company but rather an avid orchid hobbyist that happens to be a knowledgeable biologist (or some kind of "ist")(sorry Rick). So we get to erase the suspicion about the new fertilizer only being a market ploy.

I bet the folks at Peters don't even know what a Phrag is much less how to provide the nutrients it needs when there is no cliff with running water! Now growers have taken some control over their own nutrients for their collections based on what works best not what sells the best.

I had a plan to make nutrient tests on wild orchids here in Peru to try to find proof one way or the other about the low K theory. But standing looking at a million orchid plants covering the trees and hill sides and then turning around and seeing more growing on rock faces and even on the old concrete bridge rail I realized it was impossible.
There is no way that all of those plants growing in all those different conditions could possible all be getting the same ratios of nutrients.

I sat down and tried to figure out how to test the variable and realized it is not possible to have a complete answer. perhaps that is why there are no published papers on the subject. but if there is someday something published I have doubt about how accurate it will be.

And then thrown in all the rest of the planets orchids that we keep all mixed together and you have an even bigger impossibility. Rick based his low K idea on his environmental work down with potassium and not published papers about orchid nutrition. He looked for published work to support the idea but found very little and certainly none that prove the theory. But it gave a justified starting point for a new improved fertilizer formula. Growers are trying it and it is working.

It seems that having a low K nutrient level may help make up for the lack of a wet cliff or optimal temperature. That is based on grower tests and not science but it seems to be working anyway.

Speaking about optimum temperature oke: ( I think you mentioned it).
During the last few years before we left California I tried to figure out if I could grow Phrags and Paphs on our outside deck during the winter. Temperature never quite gets to freezing but often down to the high 30's. For several years all paphs died quickly and the only phrag to survive almost all winter was a besseae. I was careful not to let them be too wet and fertilized with MSU as always.The last winter we were there I put out more of the same paph hybrids and three P.kovachii. This time I fertilized with the new K-lite and this time I watered them way too much, let them be wet at night and mistreated them badly. Surprisingly they actually continued to grow and not rot or collapse from the cold as the previous years. They did not grow fast or much but I could tell they were active growing. They did not suffer until the temp dropped low enough to form frost crystals on the leaves. I just poured on K-lite water to warm them up.... they did not die from the cold or wet. By the end of winter all plants were still alive. Most of the paph roots had died but the plant growth were still alive. The kovachii came through in better shape. But they survived the winter outside. That proved to me that the low K theory is valid. The use of K-lite increased the plants stamina and gave them better health that enabled them to withstand the cold temperatures that previously killed plants grown on a diet of MSU.

No I did not do a formal trial with controls but I did repeat the process until I found something that caused a difference. I attribute the plants survival of less than optimum temperatures to the low potassium of K-lite. So based on this experience alone I feel it is justifiable to recommend the use of K-lite if plant stamina and long term health is a desired result. If you want to grow bigger plants faster then force them with MSU at 200ppm but be prepared for health issues latter in life and be prepared for some species types to get sick and die and early death.

Maybe, just maybe K-lite is a wet cliff in shinning armor?

All any orchid will ever ask of you is that you do the best you can do! :noangel:

I'm done.


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## SlipperFan (Jun 7, 2014)

Thanks, Lance. All of what you just said makes sense to me. I'm not a scientist, and can only say what my own experience is. I'm not subjecting my orchids to extreme cold, but I have observed better root growth and stronger plants since switching to k-lite a year and a half ago. I'm doing a lot of my re-potting now. I have quite a few Paphs that haven't been repotted since 2011, but they were in orchiata and non-organic media. Although many old roots were rotted, there are lots of new roots since changing fertilizers. So I'm planning to stick with k-lite.


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## tomkalina (Jun 7, 2014)

Thanks Lance; your explanation makes a lot of sense. We've been fertilizing with either K-Lite or Wuxal Calcium (10-0-0 10 Ca) every 6-7 days and flushing with a very dilute solution of Dyna-Gro Mag Pro (2-15-4) every 6 weeks. We batch mix our fertilizer solutions in a 55 gal plastic drum of RO water, add a gallon of Chicago City Water (Lake Michigan source) for the micros, then add an appropriate amount of either fertilizer to reach a TDS not to exceed 100 mg/L. This irrigation solution is then pumped out of the drum with a submersible pump to water the plants. I think the equivalent fertilizer dosage in teaspoons/gal ends up being somewhere around 1/10 tsp/gal. . Seems like a lot of trouble, but so far the results support the theory that low K at low TDS feed rates works.....


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## Stone (Jun 7, 2014)

tomkalina said:


> > Thanks Lance; your explanation makes a lot of sense.
> 
> 
> 
> Tom, what ''explanation'' are you refering to? I would love someone to explain orchid physiology and ecology to me. Just to make sure I read it 3 times. Perhaps I'm a bit thick, but to me, Lance has explained absolutley nothing. Amazing BTW why do you feel the need to use dynagrow?


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## cnycharles (Jun 7, 2014)

K-lite is not a finished product, it is the initial stage of a work in progress. It will not work for all conditions and I've read here statements that for specific conditions other fertilizers would work better. It's stated openly by those who are testing to see where it does and doesn't work, because again there is no one fertilizer that will work for the many thousands of orchids that are in cultivation. It is documented in South America that mists from sea water rising up over the mountains drop dew and nutrients onto cloud forest species. There isn't necessarily any stem flow where there isn't any rain; nutrients come from different sources for different epiphytic and terrestrial zones, and there is no way that amounts and ratios would be the same in these different areas. Like mentioned, it would be extremely difficult to test nutrients for all of these different conditions 

Likely k-lite isn't the perfect final thing, it's something agreed upon as a starting point for testing, to see what does and doesn't work, let's move forward and see where it has and hasn't worked, and see how it can be tweaked towards a better tool for growing instead of arguing about it like it's expected to be the finished holy grail 


Sent from my iPhone using Tapatalk


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## ALToronto (Jun 7, 2014)

Thank you Charles. I use K-lite for orchids in organic and neutral media, but not on my living walls, which are chemically similar to limestone cliffs. I wish there were a low K product with urea/ammonia source N, but short of buying individual ingredients and blending my own, the best I can get is 25-10-10. I think my next step will be to encourage moss growth on the walls and create a N-fixing environment.


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## Stone (Jun 8, 2014)

cnycharles said:


> > see how it can be tweaked towards a better tool for growing instead of arguing about it like it's expected to be the finished holy grail
> 
> 
> 
> ...


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## Stone (Jun 8, 2014)

> the best I can get is 25-10-10.



The same K/N ratio as I mentioned above. but P too high


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## Paul (Jun 8, 2014)

Stone said:


> cnycharles said:
> 
> 
> > Well that's exactly what I think. From all the available data it should be tweaked to something like this: IMO
> ...


----------



## gonewild (Jun 8, 2014)

The idea of the basic K-lite formula is to use it and adjust as needed.
"As needed" should be based on observations of how the plants grow using it.

Has anyone using K-lite seen a need to increase the potassium level? 

Has anyone using K-lite seen a need to decrease the phosphorous level? (that would be a result of raising the K level).


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## ALToronto (Jun 8, 2014)

gonewild said:


> The idea of the basic K-lite formula is to use it and adjust as needed.
> "As needed" should be based on observations of how the plants grow using it.
> 
> Has anyone using K-lite seen a need to increase the potassium level?
> ...



Lance, I don't think it's all that straightforward. My living wall plants did not do well with K-lite. I have no idea what exactly was the problem, but I suspect it wasn't one thing. They do better with 25-10-10, even with excessive P which is causing algae growth on the wall and is probably also feeding the mushrooms that are growing in the branches.

The only way to determine conclusively how much K is needed is to run a multi-factor experiment which will test for the individual main effects (N, P, K, Ca/Mg) as well as their interactions. That's four factors (assuming Ca and Mg are kept in the same ratio and are varied as a pair). That's a lot of different formulations, while keeping all other factors constant (temp, humidity, medium, watering schedule, etc). 

I've offered before, and I'm still willing to design this experiment, as long as someone can 'donate' a bunch of plants and is prepared to be extremely diligent and organised for a year or two, not confusing the formulations. Don't we have some people here with access to lab facilities?


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## gonewild (Jun 8, 2014)

ALToronto said:


> Lance, I don't think it's all that straightforward. My living wall plants did not do well with K-lite. I have no idea what exactly was the problem, but I suspect it wasn't one thing. They do better with 25-10-10, even with excessive P which is causing algae growth on the wall and is probably also feeding the mushrooms that are growing in the branches.



I assume the K-lite formula to be aimed at growing in conventional media and containers or mounts. As I recall didn't you make the walls out of cement? pH of root area?



> The only way to determine conclusively how much K is needed is to run a multi-factor experiment which will test for the individual main effects (N, P, K, Ca/Mg) as well as their interactions. That's four factors (assuming Ca and Mg are kept in the same ratio and are varied as a pair). That's a lot of different formulations, while keeping all other factors constant (temp, humidity, medium, watering schedule, etc).



That is what is needed and would be great to see the results. But in the end it still would not address the effects of the nutrients under the different conditions growers maintain. The informal group trial of different people using K-lite should return an answer that is useful to orchid hobbyists, shouldn't it? 
And if you keep all the environmental conditions constant wouldn't that limit the value of the nutrient results to those specific conditions?



> I've offered before, and I'm still willing to design this experiment, as long as someone can 'donate' a bunch of plants and is prepared to be extremely diligent and organised for a year or two, not confusing the formulations. Don't we have some people here with access to lab facilities?



A year or two trial would not give the answer concerning long term plant health. That issue is when a plant that has several years or more growth and is doing well just suddenly declines or gets rot for what seems like no reason.
Then you have the problem of how you measure the result. Dry weight? Beauty? amount of flowers? I think somehow a judgement criteria needs to be accepted as to what a "healthy" plant is.

I don't see the K-lite fertilizer use as a trial to prove orchids need less K but rather a trial to determine if lower K applications generally increases the growth quality of generic orchid collections. So for me the results people report about K-lite have even more horticulture value than results from a well organized controlled trial. 

I would love to see you design a trial and see the results, because that would tell us if low K should or could be applied to commercial forcing of orchid plants. 
But commercial forcers of Phals (and others) have no interest in growing a plant that has a long life after sale, they are designed to be disposed of and replaced.

I'm interested in all the results from all sources.


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## ALToronto (Jun 8, 2014)

gonewild said:


> I assume the K-lite formula to be aimed at growing in conventional media and containers or mounts. As I recall didn't you make the walls out of cement? pH of root area?



It's a low pH mineral composite. The root area pH started at 8.5-9, but went down to 6.5 within a month. The pH wasn't the problem, I think it was more an excess of Ca and insufficient organic media to help 'digest' the nitrate. In any event, the PlantProd did the trick. That doesn't mean that it was the best possible solution.


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## gonewild (Jun 8, 2014)

ALToronto said:


> It's a low pH mineral composite. The root area pH started at 8.5-9, but went down to 6.5 within a month. The pH wasn't the problem, I think it was more an excess of Ca and insufficient organic media to help 'digest' the nitrate. In any event, the PlantProd did the trick. That doesn't mean that it was the best possible solution.



Curious. did you start out using K-lite and for how long did you use it before changing?
Did any algae or other things start growing before switching?

Now it would be interesting to see what would happen if you switched back to K-lite. It may have had something to do with the base material stabilizing and leaching out whatever minerals it is made of.


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## ALToronto (Jun 8, 2014)

I switched quickly because with K-lite, the pH of my irrigation water was above 8.5 - and that's with RO water. It wasn't going to bring down the pH of the wall. Time to give it a try again.


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## gonewild (Jun 8, 2014)

ALToronto said:


> I switched quickly because with K-lite, the pH of my irrigation water was above 8.5 - and that's with RO water. It wasn't going to bring down the pH of the wall. Time to give it a try again.



It will be interesting to see the result of switching back to K-lite. Maybe the lower K level will allow a better balance of the micro fauna and the algae will be less. 

Prior to putting the plants on the wall had you been fertilizing them with K-lite?


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## ALToronto (Jun 8, 2014)

gonewild said:


> It will be interesting to see the result of switching back to K-lite. Maybe the lower K level will allow a better balance of the micro fauna and the algae will be less.
> 
> Prior to putting the plants on the wall had you been fertilizing them with K-lite?



Yes, I had been giving them K-lite and occasional seaweed extract, and they were doing very well. That's why it felt so wrong to go to a conventional fert.

That said, with my most recent wall, the one I posted about a few days ago, I put a couple of catts that were stagnating in their pots, in bark and coconut chunk mix. They took off on the branches, and I just spotted a sheath on the newest growth of one of them. Just goes to show that there are no simple, single factor solutions - would these catts have been struggling with K-lite if they had not been potted in coconut?


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## Ray (Jun 9, 2014)

ALToronto said:


> I switched quickly because with K-lite, the pH of my irrigation water was above 8.5 - and that's with RO water. It wasn't going to bring down the pH of the wall. Time to give it a try again.



Was that a large-batch solution, or a small grab from the powder? I ask, because we know it's not the most finely ground or uniformly dispersed material, and when I make up a concentrate with several pounds of powder in RO, I am consistently seeing a pH in the 5.0-5.5 range (Greencare adds citric acid to aid dissolution in stock tanks).


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## Brabantia (Jun 9, 2014)

ALToronto said:


> That said, with my most recent wall, the one I posted about a few days ago, I put a couple of catts that were stagnating in their pots, in bark and coconut chunk mix. They took off on the branches, and I just spotted a sheath on the newest growth of one of them.



This fact is not exceptional we are on the season during which most of the Cattleyas are starting their new shoots.


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## Brabantia (Jun 9, 2014)

Ray said:


> Was that a large-batch solution, or a small grab from the powder? I ask, because we know it's not the most finely ground or uniformly dispersed material, and when I make up a concentrate with several pounds of powder in RO, I am consistently seeing a pH in the 5.0-5.5 range (Greencare adds citric acid to aid dissolution in stock tanks).



I do not believe it is the added citric acid which makes that the pH of the solution is acid. Since a few years I make all my fertilizers myself (yes I like experimenting). I was never able to conceive(design) a fertilizer which did not give a slightly acid reaction in deionized water. Citric acid is probably used as a chelator.


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## tomkalina (Jun 9, 2014)

A pH of 8.5 sounds high if all your adding to RO water is K-Lite. We add 1-2 cups of K-Lite concentrate (2# dissolved in 5 gallons of RO water) to our 55 gal drum of RO and get a pH of 7.0-7.3 (Average of 12 samples over a two month period). If your feed water has a high pH, is it possible the 8.5 pH you're getting in the RO effluent may be due to membrane failure?


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## DavidCampen (Jun 9, 2014)

Brabantia said:


> I do not believe it is the added citric acid which makes that the pH of the solution is acid. Since a few years I make all my fertilizers myself (yes I like experimenting). I was never able to conceive(design) a fertilizer which did not give a slightly acid reaction in deionized water. Citric acid is probably used as a chelator.



Yes, in my formulations, I use diammonium citrate to bring the pH up to 5.7-6.3, otherwise it would be at 5.0 or below in RO water, especially when using any ammonium nitrate in the formulation (I also add borate as boric acid).


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## ALToronto (Jun 9, 2014)

Ray, I use a 4000 ppm N concentrate (33 g powder in 1L water) to mix up my fert solution. I don't think I could hit 10 ppm N with a single crystal of the powder - it would be in excess.

Without fert, my RO water is 7-10 ppm tds, and a pH of 7.5-7.8. I don't know why it went up with K-lite. Certainly if I spill some concentrate on the (traditional) concrete countertops in my kitchen, I get an acid-etched spot.

Probably time to recalibrate my pH meter and go through this exercise again.

Tom, you're right that this is active growth season. But the rate of growth of the catts on the wall, compared to the ones still in pots, is significantly higher.


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## Ray (Jun 9, 2014)

I agree on the calibration check - both pH & TDS.

Pure water, when exposed to the CO2 in the air, should give you an equilibrium pH of about 5.4 (maybe lower now that the global average has gone from 300- to 400 ppm). I cannot imagine what would increase it so much at that low TDS


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## Brabantia (Jun 10, 2014)

Ray said:


> I agree on the calibration check - both pH & TDS.
> 
> Pure water, when exposed to the CO2 in the air, should give you an equilibrium pH of about 5.4 (maybe lower now that the global average has gone from 300- to 400 ppm). I cannot imagine what would increase it so much at that low TDS


Just as remark: It is very difficult to measure the pH of a solution presenting a very low conductivity such as RO water. This is only possible by using very special electrodes and adapted electronics ... it costs a lot of money!


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## Stone (Jun 10, 2014)

Here's a sobering observation!
Last night one of our members (who grows just about every paph and phrag as well as many other things) brought in a couple of things and I asked him what he feeds.

Answer: He uses a ''professionally made'' stuff at 3 times recommended concentration on everything every week and waters like hell. He was not sure of the NPK but you can bet it wasn't low in K! He said he would not recommend it (and niether would I) but that's what he does. (Forces the crap out of everything and nothing going backwards yet) He grows everything in plain fine bark and that's it.
He benched 2 Paphs. 1 multi growth delenatii bursting out of its pot and one nice multi growth concolor with 7 inch leaves.
We still have much to learn!

I must say this notion of long term health problems really does not make sense. If you grow a plant to its optimum potential, (not so much forcing as above) and keep it coming, there is no rational reason why it should suddenly - or slowly- start a decline after a period of time. The problems come about when you start to neglect it through boredom or laziness or whatever.

Remebering that ''optimum'' is different for every plant and discovering what is optimum for each species can be difficult to impossible, It cannot be justified that a plant with nice big green leaves AND a healthy vigorous root system AND which holds on to its old leaves, is lacking Calcium, Magnesium or is intoxicated with Potassium. Its just not possible.

One of the first signs of Ca deficiency is dead or dying roots. And without them nothing else works. If it was low in Mg it cannot have dark green leaves. You can't have plenty of Mg in the chlorophyll and have K blocking it at the same time!

Fear of potassium still looking a bit misguided to me. Just don't use too much and there will be no problem.


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## Brabantia (Jun 10, 2014)

ALToronto said:


> But the rate of growth of the catts on the wall, compared to the ones still in pots, is significantly higher.



I agree, Catts are growing faster than Paphs. Unless using as some producers higher doses of fertilyser (600 - 800 µS) and in an optimal environment. At present here Catts in pots are growing crazy at 400 µS (3/1/2 fertilyser) one time per week. I am always surprised noticing that Catts are able of growing so fast with so few fertilizers while with slightly less Paphios limp along. 
I believe that it is in connection with the quantity of roots or a slower metabolism ?


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## Stone (Jun 10, 2014)

Brabantia said:


> > Catts are able of growing so fast with so few fertilizers while with slightly less Paphios limp along.
> > I believe that it is in connection with the quantity of roots or a slower metabolism ?
> 
> 
> ...


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## ALToronto (Jun 10, 2014)

Brabantia said:


> I agree, Catts are growing faster than Paphs. Unless using as some producers higher doses of fertilyser (600 - 800 µS) and in an optimal environment. At present here Catts in pots are growing crazy at 400 µS (3/1/2 fertilyser) one time per week. I am always surprised noticing that Catts are able of growing so fast with so few fertilizers while with slightly less Paphios limp along.
> I believe that it is in connection with the quantity of roots or a slower metabolism ?



I'm comparing growth rates of only catts. Most of mine are mounted, but I have a few that are potted as well - three in semi-hydro, four in bark/coconut, and two in lava rock. Of the potted ones, the semi-hydro group is doing best - but then again, I used to have a lot more in semi-hydro, and I had to pull most of them out before they died. Now the semi-hydro refugees are mounted and are doing much better.


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## ALToronto (Jun 10, 2014)

Mike, that's interesting about overdosing the fertilizer. I suspect that 'watering the hell out of them' means flushing with plain water, so overall, the fertilizer concentration is much more dilute. I'm sure the guy didn't tell you everything.

If I showed my concrete recipe to someone who is familiar only with traditional concrete, they would insist that my product wouldn't hold together. And yet it's far stronger than anything that comes out of a mixer truck. There are ways to push the envelope, but you really need to know what you're doing.


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## Stone (Jun 10, 2014)

ALToronto said:


> > There are ways to push the envelope, but you really need to know what you're doing
> 
> 
> .



Very true!


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