Pre-Sterilized · Hardwood · Organic Grain
Mushroom Substrate & Grain
Ready-to-inoculate substrates and bulk grain for spawn production. Pre-sterilized in our CFIA-licensed facility so you can skip the pressure cooker.
Ready to Inoculate
All Substrates & Grain
Pre-sterilized hardwood blocks, all-in-one pellet blends with soy hull, organic millet grain for spawn production, and bulk rye grain. All sterilized and ready to go.
Which Substrate Is Right for You?
Pre-Sterilized Hardwood (6-pack)— Supplemented hardwood sawdust blocks, sterilized and sealed. Just inject your liquid culture or break in grain spawn, seal the bag, and wait for colonization. Best for oyster, shiitake, and lion's mane.
Sterilized Magic Soil — A premium manure-based substrate blend of composted cow manure, coconut coir, vermiculite, and gypsum. Designed for dung-loving species that thrive on rich, nutrient-dense substrates. Available as singles ($39) or cases of 6 ($155). Pressure-sterilized and ready to inoculate.
All-In-One Mushroom Pellets (20 lb) — A pre-mixed blend of hardwood fuel pellets and soy hull pellets in the optimal ratio. Add water to hydrate, sterilize or pasteurize, and inoculate. Great for growers who want control over their process.
Bulk Organic Millet Grain (20 lb) — Clean, organic millet for making your own grain spawn. Small kernel size means more inoculation points and faster colonization than rye or wheat.
Not sure where to start? Read our substrate preparation guide or try the bulk substrate calculator.
Frequently Asked Questions
What is the best substrate for growing mushrooms?
The best substrate depends on the species. Hardwood sawdust (supplemented with bran or soy hull) is ideal for oyster mushrooms, lion's mane, and shiitake. Manure-based substrates like our Magic Soil work best for dung-loving species. Straw is popular for outdoor oyster beds. All substrates must be sterilized or pasteurized before use.
Do I need to sterilize mushroom substrate?
Yes — supplemented substrates (hardwood with bran, manure blends, grain) must be pressure-sterilized at 15 PSI for 90-120 minutes. Plain straw can be pasteurized instead. Our pre-sterilized substrates skip this step entirely — they arrive ready to inoculate.
How much substrate do I need per bag of spawn?
A standard spawn-to-substrate ratio is 10-20% by weight. One 5 lb bag of grain spawn can inoculate 25-50 lbs of bulk substrate. For our pre-sterilized hardwood blocks, use approximately 1 lb of grain spawn or 3cc of liquid culture per block.