Substrate calculator
Enter your bag or bucket size and choose a recipe. The calculator returns dry-ingredient amounts, water volume to field capacity, and recommended sterilization or pasteurization time.
For
About the recipes
- Masters Mix — hardwood fuel pellets + soy hulls. Best for high-yield bulk grows of oyster, lion's mane, king oyster. Field capacity ~65% moisture.
- Pasteurized straw — classic beginner method. Best for oyster mushrooms in 5-gallon buckets. Hot-water pasteurize at 65–74 °C for 1 hour.
- CVG (coir + vermiculite + gypsum) — clean, sterile bulk substrate. Best for grain-spawned monotubs.
- Supplemented hardwood sawdust — hardwood + wheat bran (10–20%). Best for lion's mane and shiitake. Requires pressure sterilization.
Spore safety
Wear an N95 mask when mixing dry substrate and when opening fruiting chambers. Substrate dust and mushroom spores can cause hypersensitivity pneumonitis ("mushroom worker's lung") with repeated exposure.