Powdered gypsum is used to increase the pH in mushroom growing substrates such as coco choir, sawdust, coffee grounds and straw. It is a yield enhancer as it supplies minerals and trace elements to the mycelium.
It is also used when preparing grain spawn to stop the grain from clumping together.
Gypsum should be mixed at a rate of 2.5% of the dry weight of the bulk substrate and 1 tablespoon per litre of grain spawn.
The product of powdering brown rice is a popular substrate for growing mushrooms. Its use as a substrate was made popular by the use of cake spawns in the PF Tek method of growing. It is most often powdered into a flour and combined with vermiculite.
Hardwood sawdust is used to grow wood loving mushrooms such as Shitake, King Oyster, Wine Cap, Chicken of the woods, Turkey Tail, Lions Mane, Maitake and Reishi mushrooms.
Our hardwood sawdust is from meranti.
Paul Stamets Sawdust Recipe:
73 % Hardwood Sawdust
24.6 % Bran
2.4 % Gypsum
65% water added to the above mix.This mixture is added to a mushroom grow bag and steralized at 15psi for at least 2 hours ( depending on the size and amount of bags being steralized.Once cooled grain spawn is added, the bag is sealed for sterile colonization.