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Calcium Magnesium questions

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consettbay2003

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As I am unable to locate a source for MSU fertilizer in the U.K. I would like some information on supplementing my regular fertilizer with these two elements. From what I have read it seems to be the concensus not to mix calcium nitrate and magnesium sulfate together as this will cause a precipitation of calcium sulfate to occur. I have mixed 1/2 tsp calcium nitrate and 1/2 tsp magnesium sulfate in one gallon of RO water and see no evidence of a precipitate forming.

Comments are welcomed.
 

likespaphs

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i can't remember what it is but there is a ratio at which calcium and magnesium should be used as they can be antagonistic.
you could look around for a fertilizer at a plant seller which would be labeled 'cal-mag' or something similar...
 

gonewild

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You won't see precipitates until you mix stronger concentrations. At concentrations that you would apply directly to your plants you won't have a problem. If you try to mix a concentrated solution to use with a fertilizer injector then you may have the problem.
 

consettbay2003

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I checked the Antec website and they seem to think 30-50 ppm calcium and 20-30 ppm magnesium is adequate for paphs., so it looks like a ration of 2 calcium nitrate: 1 magnesium sulfate would be acceptable.
 

gonewild

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You can make your own MSU fertilizer, just follow the recipe on the label to get thge ratio of nutrients correct:

Total Nitrogen……………………………….….13%
12.5% Nitrate Nitrogen
0.7% Ammoniacal Nitrogen
Available Phosphate (P2O3)…………………..….3%
Potash (K2O)……………………………………15%
Calcium…………………………………..…….8.0%
Magnesium………………………………..……2.0%
Iron (Fe)……………………………………...0.177%
Manganese (Mn)…………………………..…0.088%
Zinc (Zn)…………………………………..…0.041%
Copper (Cu)……………………………….…0.044%
Boron (B)………………………………….…0.018%
Molybdenum (Mo)…………………………..0.018%
 

consettbay2003

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excuse me:confused: Remind me to send you a batch of my home made cookies, so you can see how good I am with a recipe! I was one of the nerds in the back row of the chemistry class.
 

gonewild

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consettbay2003 said:
excuse me:confused: Remind me to send you a batch of my home made cookies, so you can see how good I am with a recipe! I was one of the nerds in the back row of the chemistry class.
:rollhappy:

I thought nerds were the ones who did well in class?
How is your math?

On the MSU fertilizer analysis you can see the calcium to magnesium ratio is 4:1. Bob at Antec stated that he feels it should be higher in magnesium for paphs and phrags.

Don't forget when you calculate how much to add to your fertilizer you need to base it on the % of the nutrient and not the volume. 4:1 does not mean 4 spoons of Calcium nitrate with one spoon of Magnesium sulfate.
 
I

IdahoOrchid

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Is calcium nitrate a source of calcium, nitrogen or both?
 

consettbay2003

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It's a source of both calcium and nitrogen (nitrate form)

I am planning on using 1 tsp Calcium Nitrate to 1/4 teaspoon Magnesium Sulphate as an feeding in between regular fertilizing. My regular fertilizer contains 2% MgSO4 but no calcium.
 

Hien

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I am kind of lazy to do too much mixing & measuring, Can I just use the dolomite lime from garden center?
(since they list both calcium and magnesium as components of the dolomite lime)
 

Rick

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gonewild said:
You won't see precipitates until you mix stronger concentrations. At concentrations that you would apply directly to your plants you won't have a problem. If you try to mix a concentrated solution to use with a fertilizer injector then you may have the problem.
The formation of calcium sulfate is also driven by high pH, and since you'll be staying under 9 s.u. with this mix you will need to get pretty high concentrations to cause the gypsum to form.
 
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Bob Wellenstein

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You need not be concerned, Eric, about the pH and precipitation unless you are mixing concentrates for injectors. At that concentration the mixture stays in solution because it is quite acidic. You cannot alter the pH or you will form precipitates, so we use a second injector with a potassium bicarbonate solution to inject behind the fertilizer. Again, only a concern for those mixing very concentrated solutions.
 
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charlie c

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Lynn/Bob,

In your experience, is there any benefit/detriment to feeding Epsom Salts on a regular low dose regimen (say, 1/4 teaspoon per gal every watering) as opposed to the large bolus every month or two?

charlie c
 

gonewild

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NYEric said:
I'm just hoping everything I need is in the fertilizer and MSU formulas.
Bob made a point that fertilizers don't have enough magnesium content for slippers. He recommended applying additional every few months. There seems to be no published exact ratio between calcium and magnesium that is proven to be best. But Bob certainly knows from his experience that paphs and phrags like more magnesium than supplied by the MSU formulas. I'm going to add additional magnesium to my fertilizer solution to see what happens.
 

Rick

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gonewild said:
Bob made a point that fertilizers don't have enough magnesium content for slippers. He recommended applying additional every few months. There seems to be no published exact ratio between calcium and magnesium that is proven to be best. But Bob certainly knows from his experience that paphs and phrags like more magnesium than supplied by the MSU formulas. I'm going to add additional magnesium to my fertilizer solution to see what happens.
I spike my low pH (6-6.5) with a dash of magnesium sulfate. For my higher pH plants (7-8) I use a dash of magnesium hydroxide.
 

NYEric

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Umm, when I go downstairs to the supermarket do I ask the manager " Where do you keep your magnesium sulfate and magnesium hydroxide?"!?
 

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