I have used garden gypsum and MG in the past but never knew how much. I also like the idea of getting a powdered form of gypsum to add right with my fertilizer.

Any ideas?

Let's keep it straight for other readers who might be researching these mixes.

Dolomitic Garden Lime goes in the 5-1-1.

Gypsum goes in the Gritty Mix.

When using Gypsum in your mix, you add Epsom Salts to your fertilization water.
However, as Al has many times stated, if you have a fertilizer that supplies
all the essential nutrients, then you don't need to add the Gypsum to the Gritty Mix.
Since you are purchasing or have purchased Foliage Pro, you don't need Gypsum necessarily.

As for the peat moss questions....I advise you to make a Lime peat moss mix and to simply
test the pH of the saturated mix. Then you can tell us how Lime affects the ingredient.

Josh

"When using it in the 5-1-1 and other soil less mix's I know there is Ca/Mg from the lime but no Sulfur, could it hurt to use the gypsum?"

From what I've read, S deficiencies in container plants are rare, so I wouldn't add gypsum just for the S. Lime has a proper Ca:Mg ratio, and adding more Mg will just throw that off.

Thanks both of you guys. I tend to over think things. I am not sure if I am going to get FP even though I made a post on what is the best dyna-gro, not sure if the cost is where I want it to be for this application.

Thanks for the info. Was not sure if the lime would get me through the season for tomatoes.

Thanks.

First off I want to say I never realized posting a link on here was spam. I am sorry for all the links I may of posted though I always provided the source.

I found S is needed. If I dont use FP should I use gypsum?
I found a slow release that has all micro including S in it, should I just use that? I grow edible gardens that require more food than most plants.

"From what I've read, S deficiencies in container plants are rare, so I wouldn't add gypsum just for the S. Lime has a proper Ca:Mg ratio, and adding more Mg will just throw that off."

I am using a soilless medium using MG with no S. Are you sure I should not use gysum? Will it really throw it off even If I use a just a touch? Should I just use ammonium sulfate?

I dont want to miss out on sulfur.

Thanks.

There are many people that use fertilizers with no S in soilless mixes. The plants must get enough S from the tap water, decaying organics in the soil mix, or even the air. If you're concerned about it, you could add gypsum to your mix, and epsom salt to your water. This would supply Ca, Mg, and S in a more balanced manner. Al recommends 1 Tbs of gypsum per gallon of soil mix, and 1/8-1/4 tsp of epsom salt per gallon of water when fertilizing.

Thank you!!! So I am ok to balance with lime, then use gypsum and epsom salts in the manner you described? Thank you for your help.

Typically one uses either lime, or gypsum + epsom salt, not both. Using lime and gypsum + epsom salt would be double dosing your Ca and Mg, and would unnecessarily increase the TDS in the soil. It's true that lime alone does not supply S, but I imagine the highly organic soils it's used in do supply sufficient S. I've never heard of any S compounds being recommended for the 5-1-1 mix, and plenty of people successfully use that with S-free MG fertilizer.

Al may be able to offer a more definitive answer.

Thank you very much, yea maybe I could find out why we can get away with out the S, I would really like to know.