# Which MSU formulation?



## paph_deb (Jan 17, 2016)

I’m looking at using MSU-type fertilizer but am not clear on whether to go with the RO/pure or well/hard water formulation. Choosing is difficult due to the differing descriptions on vendor sites. I will be using Memphis tap water, which is pretty soft but which does have calcium and magnesium ...

Memphis Light, Gas and Water’s 2014 Report (http://www.mlgw.com/about/waterqualityreport) provided the following:
Alkalinity	55 ppm
Hardness	47 ppm
Hardness	2.7 grains/gallon
pH 7.2 

Per the Magnesium Website Online Library (http://www.mgwater.com/mgrank.shtml#ordered), Memphis water has:
Magnesium	4.41 ppm
Calcium	9.01 ppm

Per the Center for Magnesium Education and Research (http://www.magnesiumeducation.com/magnesium-in-drinking-water), we have:
Magnesium	4.45 ppm
Calcium	7.9 ppm

So ... which formulation sounds most appropriate to you guys? I can certainly water with no fertilizer one week a month to help flush out any accumulating salts. Sound good?


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## NYEric (Jan 17, 2016)

Um,, are you using tap water or purified/filtered water?


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## paph_deb (Jan 17, 2016)

As stated, tap water.


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## NYEric (Jan 18, 2016)

then you should probably use the one with less additives, for "tap water".


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## naoki (Jan 18, 2016)

Sounds like nice water. I'm guessing that either one will work.

If you target 30ppm N with pure water formula, you'll be getting 18.2 ppm of Ca and 4.5ppm of Mg.

As a related note, I wonder if well-water formula is less likely to precipitate in the stock solution.


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## paph_deb (Jan 19, 2016)

Thanks for the help. Much appreciated.


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## Ray (Jan 19, 2016)

At such low concentration, precipitation is unlikely with either formula - or K-Lite - and there is no potential of overdoing the calcium or magnesium. 

Your comment on flushing begs the question of whether your media dry between waterings? If so, a periodic flush will do very little to redissolve the residues. 


Ray Barkalow (via Tapatalk)


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## paph_deb (Jan 19, 2016)

That's useful info, Ray. I'm so new to this that I don't know how dry the media is getting, but most of my (very small) collection of plants are paphs, so I'll be working to keep them happily moist. 

If there are dried residues, does it help to soak the pot for a short time and then flush? (I don't think I'll have that problem, just trying to get my head around the watering/fertilizing concepts.)

Again, thanks. This such a helpful forum ... and so is your website!


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## Ray (Jan 20, 2016)

Deb. 

I think the easiest way to water and feed is often and very dilutely, mimicking what the plants see in nature. That'll mean using a more "open" potting mix, but that's good for the plants, too.

I just finished responding to someone who had purchased the MSU WW formula, then, at a friend's advice, applied it at one ounce per gallon, which is roughly 1600 ppm N. Time for some flushin'!!! I'm guessing that the friend bought theirs from RepotMe.com, who sells a made-up liquid version, yet (illegally) doesn't change the formula on the label...


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## paph_deb (Jan 20, 2016)

Yikes, Ray. That was some over-fertilizing! 

I have heard the good advice of feeding weekly, weakly (or is it weakly, weekly?) and that's my plan.


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## Ray (Jan 21, 2016)

paph_deb said:


> Yikes, Ray. That was some over-fertilizing!
> 
> I have heard the good advice of feeding weekly, weakly (or is it weakly, weekly?) and that's my plan.



The only issue I have with that advice is that "weakly" has no meaning.


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## gonewild (Jan 21, 2016)

Ray said:


> The only issue I have with that advice is that "weakly" has no meaning.



Neither does "weekly" to a plant. 
Plants need to consume a steady supply of nutrients all day long everyday....


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## Happypaphy7 (Jan 21, 2016)

Please stop twisting around the phrase.
I'm sure you guys know what is meant by weekly weakly.
Not too strong a concentration of fertilizer each or every other watering (depending on the watering frequency).

And people know this is just a general guide. There are no numerical values assigned in that phrase, are there?
and no one water constantly their orchids in pot. They will have no roots left in no time.


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## paph_deb (Jan 21, 2016)

To my mind, the phrase weakly, weekly (or weekly, weakly) isn't meant to be taken literally. It's simply a memorable way to say that low, regular feeding is better than periodically blasting a plant with ferts and/or feeding erratically. It's pretty much the same advice as feeding a dilute mixture regularly in order to replicate nature's rhythms. 

ETA: Yep. What Happypaphy7 said.


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## Ray (Jan 22, 2016)

Happypaphy7 said:


> Please stop twisting around the phrase.
> I'm sure you guys know what is meant by weekly weakly.
> Not too strong a concentration of fertilizer each or every other watering (depending on the watering frequency).
> 
> ...



That's precisely my point. "Not too strong" is equally meaningless to anyone but you. Not everyone defines it the same way. If folks want to give *good* advice about feeding, then the formula, concentration, and feeding frequency ALL need to be considered and specified.

Concerning your watering comment, I disagree with that, as well. About 20 years ago, I split 300 seedlings of a phalaenopsis hybrid and an oncidium hybrid into two, approximately equal groups, and got them all established and growing in S/H culture, where they have a constant water supply. Half were watered about once every 4-5 days, the other half were watered every day. At the end of 6 months of that treatment, none of them lost roots and died, and the ones I watered daily were larger than the "control" group.

"Overwatering" does not cause root loss. "Underaerating" due to the use of a suffocating medium is what does it, and you may compensate for that by reducing your watering.


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## gonewild (Jan 22, 2016)

Ray said:


> "Overwatering" does not cause root loss. "Underaerating" due to the use of a suffocating medium is what does it, and you may compensate for that by reducing your watering.



100% correct.

Be aware that when you compensate by reducing your watering frequency you also reduce the nutrient availability during the "dry" periods between watering. And that reduces growth.

Best growth can be achieved by using a media that allows watering everyday and then taking time to water that often.


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## Rick (Jan 22, 2016)

paph_deb said:


> Thanks for the help. Much appreciated.



paph_deb

Are you in the Memphis Orchid Society?


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## Happypaphy7 (Jan 22, 2016)

I guess I'll just repeat stuff I have already said.
By "weakly, weekly", and/or "not too strong", people understand what it is meant, so don't say it is meaningless to anyone but me. 
See, the person who started this thread said so as well. I doubt we are the only two people, because the phrase is not my invention.

Perhaps it's just meaningless to you. oke:
but I know it's not. Even you get it. What you meant to say is it is vague.
That's why I said it's a general guide line. Gosh! Please read and get the point, and please be nice.

Fertilizer bottles or bags come with instructions. 
By this rough guide line of "weakly", no one in the right mind will overdose.
Hence, at least you are not likely to burn the plant.
Now, if you want to get into the details, I know different people use different dilution. Full strength, half strength, quarter strength, and I've heard even less, and these all seem like a personal choice. All these people grow great plants. 
Also, I started a thread about my friend's orchids growing and flowering perfectly fine after not having been fed for about one year.
Of course, fertilization is necessary under cultivation.

Regarding overwatering, I guess you have a different definition of the expression, or else, I see overwatering and underaerating as the same thing. At least, in certain settings where soil or dirt is used for potting medium, they are the same but said differently because after watering, air pockets in the potting mix will be saturated with water initially. Then, as the water drains, is taken up by plants, and dries out, the air pockets will increase, or should I say restore?

With open mix like bark, I don't know how overwatering ( since there are still plenty of "air room") kills roots, but it seems to happen unless it is an act of pathogenic organisms that attack roots.

I believe you on your experiment on S/H, and many other people have successful results, but not every plant adapts well to S/H.
Also, your comparison of two watering groups, it only makes sense since plants are mostly made of water. 
You see basically the same results in orchids in bark mix. The one that are well watered grow to their full potential, and the ones that are underwatered will not grow as large or even get crinkled due to lack of water while in active growth. 

Now, how about this one, I know people who grows cattleyas among other things, in water. Not S/H, but in water. So, there is very very poor aeration, but no root death. 
Your explanation is not all that there is not completely correct.
So please don't say "it's meaningless to anyone but you" kind of stuff here.







Ray said:


> That's precisely my point. "Not too strong" is equally meaningless to anyone but you. Not everyone defines it the same way. If folks want to give *good* advice about feeding, then the formula, concentration, and feeding frequency ALL need to be considered and specified.
> 
> Concerning your watering comment, I disagree with that, as well. About 20 years ago, I split 300 seedlings of a phalaenopsis hybrid and an oncidium hybrid into two, approximately equal groups, and got them all established and growing in S/H culture, where they have a constant water supply. Half were watered about once every 4-5 days, the other half were watered every day. At the end of 6 months of that treatment, none of them lost roots and died, and the ones I watered daily were larger than the "control" group.
> 
> "Overwatering" does not cause root loss. "Underaerating" due to the use of a suffocating medium is what does it, and you may compensate for that by reducing your watering.


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## Happypaphy7 (Jan 22, 2016)

*Be aware that when you compensate by reducing your watering frequency you also reduce the nutrient availability during the "dry" periods between watering. And that reduces growth.
*

I doubt this difference is of any significance unless you mean like a month of not watering.
Even orchids that have not been fed for a long time, but just plain water grow and bloom fine for a limited time, so by skipping fertilizing here and there cannot hurt, or at least the difference caused by such "laziness" if any, will not be noticeable to us.

* Best growth can be achieved by using a media that allows watering everyday and then taking time to water that often.*

Yes and no. In theory, yes, when water and nutrients are provide in enough quantity when the plants need them, sure they will grow to perfection.
But no, because for example of paphiopedilum that mostly grow on limestone with some debris collected at the root area, even during the actively growing phase, the rain is not there every day, although rain is frequent and it can be for days on end. They are designed to withstand some period of "drought" without harm.
Sure there will be morning dews and stuff that provide water little bit on a daily basis.

So strictly speaking, daily watering being the ideal is not the only way. You can skip a day or two, and still be fine.

We know that there is a member in Norway who use mainly small stone chips as potting mix and water almost daily. We've all seen the results.
So yeah. 
But for many of us, especially indoor growers like me who cannot not just liberally hose down in an apartment can't afford to do this. and watering daily is also not practical nor possible. There are other things to do other than watering. Plus, when you have hundreds of plants. oh, no~


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## gonewild (Jan 22, 2016)

Happypaphy7 said:


> But for many of us, especially indoor growers like me who cannot not just liberally hose down in an apartment can't afford to do this. and watering daily is also not practical nor possible. There are other things to do other than watering. Plus, when you have hundreds of plants. oh, no~



Exactly. You dont have the time or ability to water every day. The spacing between watering is for your benefit not the plants.


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## Happypaphy7 (Jan 22, 2016)

Duh, yeah, of course! 
Cultivation, no more in situ. lol


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## OR.O (Jan 23, 2016)

little question:
Is it possible watering every time with a fertilizing like MSU formula at 100/130ppm ? Is it too much ?


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## Rick (Jan 23, 2016)

OR.O said:


> little question:
> Is it possible watering every time with a fertilizing like MSU formula at 100/130ppm ? Is it too much ?



100 to 130 ppm total (NPK fert),or just nitrogen concentration?

And "every time" as in once a day, once a week or once a month?

I apply water with fert (especially mounted plants) every day at the rate of 2-5 ppm Nitrogen. I also have plants (mainly phrags) in semi hydro-like systems (so access to water continuously 24/7/365 days a year) that get daily top up and/or flush with the same water. I have not used MSU or other high potassium feeds for over 5 years now, but base my feeding on a low K program (K concentration now less than 1 ppm with daily fertigation).

My results are under this program are superior (for survivorship, growth rate, disease resistance...) to when I used MSU Pure Water once a week at the rate of 80-100ppm N (about 1/2 tsp per gallon or 650ppm total fert) with 3-5 waterings in between with no feed in between the weekly feeding.

So if you clarify you question a bit more it would be easier to answer your question. I think you might have good results with 100-130 ppm (total fert) if added to a basic soft to moderately hard water, watering every 3 or so days.

At 100ppm total fert that should be about 15ppm N.


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## paph_deb (Jan 23, 2016)

Rick said:


> paph_deb
> 
> Are you in the Memphis Orchid Society?



I'm looking forward to stopping by tomorrow's meeting — the first one I've ever attended.


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## Rick (Jan 23, 2016)

paph_deb said:


> I'm looking forward to stopping by tomorrow's meeting — the first one I've ever attended.



It's an awesome group with very good growers. You should ask them about the nutrition presentation I gave there this past October.


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## C. Rothschild (Jan 23, 2016)

If this is about those orchids from Hauserman's I believe they usually use medium to small pine bark. Sometimes a little moss but not usually.. I don't know if that helps any. That's just what I noticed from a couple orders from last year.


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## OR.O (Jan 23, 2016)

Rick said:


> 100 to 130 ppm total (NPK fert),or just nitrogen concentration?
> 
> And "every time" as in once a day, once a week or once a month?
> 
> ...



I'm sorry if I was not clear enough, 
I meant of total fert, 
the composition is (11,8N+2,7P2O5+13,7K2O+11,8CaO+3,5MgO+4,8SO3)
I use RO water and watering every about 3 days in cold seasons


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## Bjorn (Jan 24, 2016)

Happypaphy7 said:


> *
> 
> We know that there is a member in Norway who use mainly small stone chips as potting mix and water almost daily. We've all seen the results.
> *


*

Happy, pure chips is rarely used, but more often, addition of chips as a kind of extender and to get some weight of the pots which tend to be very small taken the plant size into consideration. A few species seem to benefit from almost pure limestone chips, particularly vietnamese ans possibly hangianum. The very draining properties of those mixes makes daily watering almost necessary during summer. Besides that, I've said it before and I repeat it here, many of you folks are too afraid of watering. If deceases is a problem or root rot, then its normally something else than the watering schedule that is to blame. Time to rewiew growing pratices?*


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## Bjorn (Jan 24, 2016)

OR.O said:


> I'm sorry if I was not clear enough,
> I meant of total fert,
> the composition is (11,8N+2,7P2O5+13,7K2O+11,8CaO+3,5MgO+4,8SO3)
> I use RO water and watering every about 3 days in cold seasons



I am adding a similar amount of fertiliser to all my water. My plants all get this mix most of the time except these days I have stopped the fertiliser for a while.a break during Dec to Feb. I use water from a bog nearby, so it probably contains some nutrients, but I still pay a lot of attention to the micros in the fertiliser. With RO water, the micros become even more important. Backmixing in a certain fraction of tap water sems sensible to me(Rick does it) to avoid serious micro-deficiencies. Good luck


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## Happypaphy7 (Jan 24, 2016)

Thanks for the clarification regarding your mix. 

True, watering alone of course does not harm plants, but only helps make plants grow.
Root rot, I understand this is technically off, by overwatering, which many people experience, is not the same thing as root rot caused by certain pathogenic organisms, but it can also be hard to tell what's what.
Overhead watering also help spread certain disease organisms from plant to plant when there is an outbreak.

I don't believe in lime stone either as many others do, and supposedly "line stone" species grow just fine with conventional potting mix. 

Lots of variables. 
One thing is sure and that is to use more open mix that allows frequent watering without causing harms like the way you practice. 
I don't want to water everyday but I do have some Paphs in very open mix of chunky bark and perlite, and I can water these more often than others as they dry out so much faster. These have the best roots and the above the root portions. 









Bjorn said:


> Happy, pure chips is rarely used, but more often, addition of chips as a kind of extender and to get some weight of the pots which tend to be very small taken the plant size into consideration. A few species seem to benefit from almost pure limestone chips, particularly vietnamese ans possibly hangianum. The very draining properties of those mixes makes daily watering almost necessary during summer. Besides that, I've said it before and I repeat it here, many of you folks are too afraid of watering. If deceases is a problem or root rot, then its normally something else than the watering schedule that is to blame. Time to rewiew growing pratices?


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## Rick (Jan 24, 2016)

Bjorn said:


> Backmixing in a certain fraction of tap water sems sensible to me(Rick does it) to avoid serious micro-deficiencies. Good luck



I think there's plenty of micros in the MSU or K lite already (even at the low dose I use). From the analysis of local water in TN the micros in tap water are at lower levels than you'd get at 100ppm total product use rate.

However, there's still other macros that are short in MSU common in many surface waters such as sodium, sulfate, chloride, and sometimes silicates.

If you are using MSU in RO water and really thin it down the amount of soluble Ca and Mg gets pretty low and is augmented back to normal levels with most surface waters.


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