Pasteurise for straw mushrooms: hot water at 60 to 65 degrees for 20 to 30 minutes in the oyster folder, or 65 to 70 degrees for one hour in the manual. Sterilise for shiitake and specialty species: bags in an autoclave. Compost for button: weeks of heaps and turnings, then Phase II heat. DMR also describes a chemical steeping method using a fungicide and formalin; label approval changes, so check it and use hot water if unsure.
Spawn rate is spawn weight per substrate weight. DMR: oyster 2 to 3 percent of wet straw, one 300 g bottle for 10 to 12 kg wet straw; milky 4 to 5 percent; button 0.5 to 0.7 percent of compost; shiitake 3 percent of dry weight.