# 15-5-30 K-Mag



## tomkalina (Mar 8, 2011)

Has anyone had any experience using this fertilizer formula on slipper orchids? Any long term negative effect to be expected using a high potash fertilizer?

Thanks, Tom


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## John Boy (Mar 8, 2011)

Funny!!! seeing a question like that.....from someone like you! Would not you be the _one_.... to answer such a question?
oke:
Igore me!


Tata,
JB


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## Dido (Mar 8, 2011)

Just try a new one wit 20-20-20 and some miracel ingedients. 

Some told me it is good. So will see it.


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## gonewild (Mar 8, 2011)

Is it white and kind of chunky and not very soluble?


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## Rick (Mar 8, 2011)

After seeing how much improvement in growth I've experienced after spiking Mg, I've been cutting back on K supplementation.

Reading some general texts on horticulture, K is preferentially sucked up by both plants and potting mixes, and is hard to get out once put in place. The ion exchange capacities of bark, CHC, and sphagnum are particularly susceptible to getting overloaded with K to the detriment of Ca and Mg. After a certain point K is antagonistic to Mg in the plants, and you need a gobbass load of it to overcome the K.

K is obviously good for root growth, but outside of the rooting "season" I would but the brakes on it.


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## Rick (Mar 8, 2011)

Tom
I've been using the RO MSU fert. from Roberts Flower for probably 9 of the 10 years I've been growing orchids (yes a mere pup compared to you). But I think I've applied some of my science background to orchid culture and seen some big cause and effect shifts in my collection with as close to empirical manipulations as I could muster in my hobby GH.

This fert mix is 12 - 6 - 13. A touch heavy on the K already, and Ca/Mg is 7/2 (which I think is too loppsided in Ca to start with).

I can't remember when I "discovered" Protekt, but I would guess about 2004. I would use it on a fairly regular basis to either raise pH, or purposely supplement the K and silicates to push for root growth (which I've had sporadic issues with certain plants over the years). So from about 2004 on I would essentially be adding more K beyond the 13% in the MSU.

I'm not sure why, but in early spring of 2009 I cut way back on Protekt use, and started spiking with Epsom salts on a fairly regular basis. Maybe it was because of some articles on ion exchange of CHC, and how you can reverse it with high doses of Ca /Mg. Maybe it was some of the data I looked up on nutrient cycling in rain forests or maybe the data I was seeing on the Ca/Mg ratios on limestones (that many of our favorite paphs grow on).

At this point it was like a light switch getting turned on in my GH, with virtually every aspect of my orchid culture drastically improving. So at this point I see no rewards at supplementing K beyond a normal balanced fertilizer, and fine tune the system to optimize magnesium availability.

At this time the only reason I would advocate a push for a high K dose would be if my normal irrigation water or potting mix was overloaded with Ca and Mg already.


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## Ray (Mar 9, 2011)

Rick said:


> The ion exchange capacities of bark, CHC, and sphagnum are particularly susceptible to getting overloaded with K to the detriment of Ca and Mg.


An interesting comment, but easy to agree with, as my understanding is that the cation exchange capacity of such organic media components is essentially zero, compared to soils, in which most-, if not all of the CEC is due to the highly-charged lattice edges in contained clays.

Did I learn that wrong?


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## tomkalina (Mar 9, 2011)

Thanks All,

Rick, everybody on this forum is a pup compared to me :wink:, but I'm willing to learn from those who have the experience . That's one of the things I love about Slippertalk ; I learn something new every day and I'm sure my plants benefit. In my case, it looks like a balanced fertilizer + Ca/Mag might be a better alternative than the high K formula. Never did use Protekt.


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## Rick (Mar 9, 2011)

Ray said:


> An interesting comment, but easy to agree with, as my understanding is that the cation exchange capacity of such organic media components is essentially zero, compared to soils, in which most-, if not all of the CEC is due to the highly-charged lattice edges in contained clays.
> 
> Did I learn that wrong?



Ray

I don't have much in the way of good data for lots of bark types, but there is a wealth of documentation on ion exchange for CHC, peat, and sphagnum.

The CHC and coir data is particularly rich. The Wellingtons' CHC "washing" protocol using Calcium and Magnesium solutions to extract the monovalent ions is a quick reference to the exchange capacity of CHC. 

Compared to inorganics like clay and zeolite, the total capacity may be reduced, but it's definitely greater than 0.

Working in the waste water areana I also get to see lots of work on peat filters to coffee ground filters, and just about anything that is porous and seems high in humic sources has some ion exchange capacity.

http://www.scribd.com/doc/15910149/Chapter-1-Introduction-CHF-in-Cation-Exchange-for-Water-Softening


Here's a link from a quick google search on Sphagnum ion capacity.


http://scholar.lib.vt.edu/ejournals/JARS/v30n3/v30n3-orr.htm


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## gonewild (Mar 9, 2011)

Rick said:


> After seeing how much improvement in growth I've experienced after spiking Mg, I've been cutting back on K supplementation.



Rick,
Can you elaborate on what you mean by "spiking"? 
How much how often in relation to the MSU nutrients.


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## Rick (Mar 9, 2011)

gonewild said:


> Rick,
> Can you elaborate on what you mean by "spiking"?
> How much how often in relation to the MSU nutrients.



It just means discontinuous additions to ammend or add (from scratch) into a batch of solution.

Unfortunately for most people my "spikes" are imprecise (Italian cooking methods).

It has as much to do with weather projects and how bright the GH conditions are.

During the summer when its hot and sunny, I may use up to a full TSP per gal in irrigation water (no MSU) once a week. If my Epsom "spiking" day occurs in conjunction with my Sunday (weekly) fertilizing day, I may add up to 1/4 tsp of Epsom with 1/2 TSP of My MSU. If everyone is already "nicely green" and look "happy" then I may skip Epsom spiking for a few weeks and just stick with MSU applications alone. During winter I'm probably doing about 1/2 or 1/4 the summer peaks.

Rick in TX started ammending his irrigation water in large batches at a known concentration, so you may get his imput too. 

I think its also important to know the Ca and Mg content of your irrigation water.

In general I FEEL that the plants would like to see as many molecules of Mg as Ca. This is a 2:1 ratio by weight of Ca to Mg (as opposed to the 3.5:1 in MSU and before adding any bone meal or lime or oyster shell to the potting mix) 

Adding bone meal/oyster shell/lime not only buffers pH, but helps keep CHC/bark/sphag from getting "poisoned" with excess K. But focus on Ca in the long run is just as bad as focus on K. Mg is much more labile in the plant and substrate systems, so I think can be a better mediator and purgitive of excess Ca and K in our plants and mixes.


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## Howzat (Mar 14, 2011)

Is there anyone who has heard about IBDU 31-0-0??
To me it is just like urea with some supplement and no P or K. This was mentioned by Jeffrey Newman of Jeffrey Newman Orchids in Hawaii, whom I met in Taiwan recently. He said to boost growth, this is the one he uses a lot. Gypsum is another additive that he uses for his orchids.


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## likespaphs (Mar 14, 2011)

i've been {occasionally} using peters 15-5-15 cal-mag special with no ill effects
http://www.petersabc.com/PDFs/Peters%20Excel/99140excel15-5-15FPL.pdf


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## Rick (Mar 14, 2011)

Howzat said:


> Is there anyone who has heard about IBDU 31-0-0??
> To me it is just like urea with some supplement and no P or K. This was mentioned by Jeffrey Newman of Jeffrey Newman Orchids in Hawaii, whom I met in Taiwan recently. He said to boost growth, this is the one he uses a lot. Gypsum is another additive that he uses for his orchids.



Gypsum is calcium sulfate.

Something with all N and no P or K could be straight ammonium nitrate (or urea). Farmers use this a lot.


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## gonewild (Mar 14, 2011)

Howzat said:


> Is there anyone who has heard about IBDU 31-0-0??
> To me it is just like urea with some supplement and no P or K. This was mentioned by Jeffrey Newman of Jeffrey Newman Orchids in Hawaii, whom I met in Taiwan recently. He said to boost growth, this is the one he uses a lot. Gypsum is another additive that he uses for his orchids.



IBDU is not a fertilizer you want to use on your orchids. It is intended for use on lawns and in agricultural operations. Not a good material that is for use in small containers. For a large grower looking for an inexpensive source of Nitrogen it is an option, but in my opinion not a good one.


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## Ray (Mar 15, 2011)

Rick said:


> The CHC and coir data is particularly rich. The Wellingtons' CHC "washing" protocol using Calcium and Magnesium solutions to extract the monovalent ions is a quick reference to the exchange capacity of CHC.


I am of the understanding that CEC involves the "capture" of ions that can be later released for the benefit of the plants. I would argue (possibly incorrectly!) that such a process may have little-to-absolutely nothing to do with CEC, but - like water softening - is simply a matter of preferential solubility.


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## Rick (Mar 15, 2011)

Ray said:


> I am of the understanding that CEC involves the "capture" of ions that can be later released for the benefit of the plants. I would argue (possibly incorrectly!) that such a process may have little-to-absolutely nothing to do with CEC, but - like water softening - is simply a matter of preferential solubility.



Did you check out the paper on sphagnum CEC or waste water application of coconut fiber? It covers aspects of what is truly ion exchange.

Some of the exchange materials would not be released until the material was digested in acids too.


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## Ray (Mar 15, 2011)

Yeah, probably just my interpretation of the relative degree...

However, the sphagnum article refers to _absorption_ along with water, not binding to the structure, as being the primary exchange mechanism.


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## cnycharles (Mar 15, 2011)

... about the grower who was using the cheap high nitrogen only fertilizer, the point that outdoor farmers would likely use something like that is likely very true, or an orchid grower who wants their plants to grow quickly so that they can sell them quickly. not necessarily for someone who has a collection that you would want to have stable growth and flowering. if you want your crop to grow quickly, and aren't planning to 'own' the plant for any period of time (like you will cut the corn or wheat at the end of the season), then that n only fertilizer could be useful

we used to have peter's 15-5-15 that we used on hanging flowering baskets at work, and things grew lush and flowered nicely. it had a good mix of nitrate and ammonium n's, but since we often need to 'hold' plants before shipping, it made it harder to control the growth once they got started. I was trying 13-2-13 cal/mag on my orchids for a while (it works great on our seedlings and cuttings at work), but felt that the plants were getting starved a bit. I think that most orchids probably can use more phosphorus than the low number, and if they are a rapidly-growing plant or the flower spike grows very quickly (like trichopilias that rocket out), you likely need more phosphorus during those times. plants like mums that have lots of small flowers, need the phosphorus when the inflorescences are emerging, or flower counts are lower, there is less branching and flowers, and the stems are brittle.

I was of the understanding from plant prop years ago (maybe it's all changed by now), that calcium once in a plant, doesn't move, so you need to have it available all the time (if you don't have it in the water, which we don't here)


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## Marc (Mar 23, 2011)

As were discussing fertilizier here allready I'm posting here and not starting a new one.

I'm able to get hold of some of the following fertilizier Peters 21+7+21+3MgO

Product data sheet

http://www.scottsprofessional.com/files/NVwOcSZw3d.pdf

Anyone have any experience with this fertilizer? Or at least someone who can give me some information if this fertilizer is suitable for Paphs?


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## Brabantia (Mar 23, 2011)

Have you read that:"_ A large proportion of the nitrogen part consists of urea, making this product extremely suitable for the cultivation of orchids_" !!!
In all the literature concerning the orchids culture urea as fertlizer is not recommended. Several articles were written on this subject also on this forum.


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## Marc (Mar 24, 2011)

Brabantia said:


> Have you read that:"_ A large proportion of the nitrogen part consists of urea, making this product extremely suitable for the cultivation of orchids_" !!!
> In all the literature concerning the orchids culture urea as fertlizer is not recommended. Several articles were written on this subject also on this forum.



Thanks for the input but after doing some quick googling and browsing the forums I found out that there are just as many people that say that you shouldn't use Urea then there are that say that you should / can use it.


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## Ernie (Mar 24, 2011)

Marc said:


> Thanks for the input but after doing some quick googling and browsing the forums I found out that there are just as many people that say that you shouldn't use Urea then there are that say that you should / can use it.



You're very right there! I have seen no facts to back urea/no urea in paphs. I just sort of imagine that, in fert formulae with lots of urea, the amount of nitrogen is somewhere between x and y. In this case, urea is ~13%, total N is ~21%, so your _available _N is somewhere between 8% and 21%. If you can live with that, it's a good fertilizer (until you prove otherwise to yourself). We use various formulas in random rotation to ensure a complete diet. MSU is used most.


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## gonewild (Mar 24, 2011)

Urea works well for fast growing plants and not so well for slower growing plants. 

Urea is a short lived nutrient source. When urea gets wet the nitrogen in it is quickly converted to ammonia (gas) and escapes into the atmosphere.
Urea was developed and intended to be applied to field crops as a sub-surface solid. That way when the ammonia is released it is trapped in the soil for plant roots to use. But when you dissolve it in water the ammonia immediately is released and probably completely gone within a few days.

When you apply a liquid fertilizer based on Urea to a well aerated media like bark there is little trapped Nitrogen for the plant roots to pick up. So even though you are applying nitrogen it is not really there for the plant to use over a period of time.

Fertilizer companies are using urea in their formulas more often now because it is cheap and looks good on the label. 

Basically urea is a waste of money and time to use it on slow growing plants like orchids.


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## SlipperFan (Mar 24, 2011)

gonewild said:


> Urea works well for fast growing plants and not so well for slower growing plants.
> 
> Urea is a short lived nutrient source. When urea gets wet the nitrogen in it is quickly converted to ammonia (gas) and escapes into the atmosphere.
> Urea was developed and intended to be applied to field crops as a sub-surface solid. That way when the ammonia is released it is trapped in the soil for plant roots to use. But when you dissolve it in water the ammonia immediately is released and probably completely gone within a few days.
> ...



Thanks, Lance -- that's the best explanation I've read.


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## Ernie (Mar 24, 2011)

Yes, an excellent explanation, Lance! Thanks, and I agree totally with the ideas. 

But I still haven't seen scientific literature on Paphs that says urea sucks. Sometimes biology breaks the rules. Need more grad students...


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## gonewild (Mar 25, 2011)

Ernie said:


> Yes, an excellent explanation, Lance! Thanks, and I agree totally with the ideas.
> 
> But I still haven't seen scientific literature on Paphs that says urea sucks. Sometimes biology breaks the rules. Need more grad students...



Well urea does not "suck" for any specific genera. It is a source of nitrogen. 
It is better than nothing and if used at correct levels should not hurt anything any more than any other fertilizer would.

Urea is a manufactured product and is not a natural mineral. Not that that matters, but we can't even begin to argue that it is "organic"?

The point is that a person may use it and assume they have more nitrogen for their plants than they actually do because of the % on the label. Because it is so unstable when exposed to air every time you open your fertilizer bag to remove a spoon full, your nitrogen escapes. After a short while your bag of fertilizer may not even have any nitrogen in it despite what the label says.

With urea you just don't get your moneys worth.

Interesting trivia fact.... In the jungle border zones of Peru Urea is the only nitrogen fertilizer that is legal to have. Why? because it won't blow up and is not good for making bombs. It is also next to worthless as fertilizer in the tropical climate even to grow grass. Walk outside with a bucket full to spread in the garden and in a few minutes the dry urea pellets have turned into a bucket of liquid.


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## tomkalina (Mar 28, 2011)

A long time ago, I read a piece in the Orchid Digest about fertilizers, and the thing I remember most is that the writer stated that the nitrogen in urea is more available at higher temperatures than lower . Any truth in this? If so, it may make more sense to use it during warmer months.


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## Erythrone (Mar 28, 2011)

tomkalina said:


> A long time ago, I read a piece in the Orchid Digest about fertilizers, and the thing I remember most is that the writer stated that the nitrogen in urea is more available at higher temperatures than lower . Any truth in this? If so, it may make more sense to use it during warmer months.



I read the same thing....


According to a book called "La science agricole"... (I will try to translate...):

Urea in the sol first become ammoniac and after nitrate. Transformation is fonction or microorganismes and, so, needs rather "high" temperature. So, nitrogen is not available if the temperature is too low.

NH4+ is strongly bond to colloid until it transformation in nitrate. 

Urea is highly soluble and can lost with water. Can be lost by volatilisation too. Urea is not recommended for sandy soil, except if it is buried. But it is very good for foliar application. 

My comments : I think Urea is not useful for almost all orchids because we lost it in watering or by volatilisation before it become available to our plants.


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