How to Make Grain Spawn for Mushrooms: Step-by-Step Guide
Quick Answer: Make grain spawn by simmering rye berries until hydrated, surface-drying, packing into jars, pressure sterilizing at 15 PSI for 90 minutes, cooling, then inoculating with liquid culture. Best grains: rye berries (gold standard, $8–15 per 5 lb bag), wheat berries (more available, $6–12 per 5 lb bag), milo/sorghum (small grain, excellent colonization, cheap at farm stores). Making your own grain spawn is the skill that separates beginner mushroom growers from intermediate ones. A $10–15 syringe of liquid culture can produce 10–15 jars of grain spawn, which in turn can inoculate 50–100 lbs of substrate. This guide takes you from raw grain to fully colonized spawn ready for use. ...