Agricultural grade gypsum can be used in many mushroom substrate recipes and as a soil amendment. Not all kinds of gypsum are the same. Certain kinds of pelleted gypsum contain a binding agent as well as lower calcium than agricultural grade gypsum does. When used in mushroom substrate, gypsum provides calcium and sulfur, which mycelium needs for healthy growth. Gypsum also acts as a pH buffer.
(Calcium content = 19.6%) (Sulfur content = 15.7%)
This sale is for one pound of gypsum