Our supplemented hardwood mushroom grow blocks are the perfect fruiting substrate for wood loving strains. We use 100% organic oak sawdust perfectly hydrated for growing mycelium. These blocks are sterilized and come ready to use. Our hardwood substrate blocks are supplemented with wheat bran, gypsum, calcium, and lime for optimal results. We use the thickest bags available, to ensure the sterility of the block. Each block is 5 lbs in an extra large bag, so they can be easily mixed after inoculation.