MSU Fertilizer Formulated for Orchids ?

[K-Sci]

Originally Posted by Ray

There’s also a 12-6-13 version for RO.

1) they are NOT truly “MSU” fertilizers
2) they ARE knock-offs formulated for-, and sold by Wayne Roberts of Roberts Floral Supply - orchidmix.com

He has defined them as “second generation” versions, but he merely adjusted the original formulations to make them be unique. If I remember correctly, he also used a pink indicator dye instead of blue.

Anyone who believes they are “improvements” is fooling themselves. Different and fine to use? Sure. Improved? No.

I was hoping you'd be able to shed some light on this subject.

Are the concentrations of Ca and Mg in MSU high enough to make a difference? Would they just precipitate out anyway due to the presence of the other ingredients.

What do you think?

-Keith

[Ray]

Originally Posted by K-Sci

I was hoping you'd be able to shed some light on this subject.

Are the concentrations of Ca and Mg in MSU high enough to make a difference? Would they just precipitate out anyway due to the presence of the other ingredients.

What do you think?

-Keith

Comparing them:

OM WW 4% Ca, 0% Mg / MSU WW 2% Ca, 0% Mg
OM RO 7% Ca, 2% Mg / MSU RO 8% Ca, 2% Mg

K-Lite 10% Ca, 3% Mg

In practical application concentrations, none should have precipitation issues

[K-Sci]

Originally Posted by Ray

Comparing them:

OM WW 4% Ca, 0% Mg / MSU WW 2% Ca, 0% Mg
OM RO 7% Ca, 2% Mg / MSU RO 8% Ca, 2% Mg

K-Lite 10% Ca, 3% Mg

In practical application concentrations, none should have precipitation issues

What about when making a concentrated stock solution.
-Keith

[Ray]

Originally Posted by K-Sci

What about when making a concentrated stock solution.
-Keith

Precipitation is an issue with any fertilizer formula (or any solution, actually), it simply depends upon the formula and the concentration.

Greencare claims that the MSU formulas and K-Lite should be limited to about 2#/gal, and while that is fine if you’re going to use that right away, over time, I know firsthand that some precipitation will occur. The solution? Make a smaller volume of a less-concentrated stock solution, so that it is more stable and will be used more quickly.

Generally speaking, those containing calcium are more vulnerable at lower stock solution concentrations, but that is why citric acid is often added to the formulas, enhancing the solubility.