Calculate exactly how much substrate, water, and spawn you need for any container size. Select your substrate type to get component ratios, hydration amounts, and expected yield ranges.

🧮 Substrate Calculator

Substrate Ratios by Species

Species Best Substrate Dry Ratio Sterilize or Pasteurize Typical Yield
Blue Oyster Pasteurized straw or HWSD+bran 5:1 HWSD:bran or pure straw Pasteurize 25–35% BE
King Oyster HWSD + wheat bran 5:1 HWSD:bran Sterilize preferred 20–30% BE
Lion’s Mane HWSD + wheat bran 5:1 HWSD:bran Sterilize 15–25% BE
Shiitake HWSD + wheat/rice bran 4:1 HWSD:bran Sterilize 15–25% BE
Reishi Hardwood sawdust (no supplement) 100% HWSD Sterilize 10–15% BE
Button Mushroom Composted manure + casing Manure bulk + 1" casing Phase II composting 20–30% BE
Enoki HWSD + rice bran 4:1 HWSD:rice bran Sterilize + cold fruiting 20–30% BE
Wine Cap (outdoor) Wood chips (garden bed) N/A — bulk garden bed None — outdoor bed Variable

Understanding Biological Efficiency (BE)

Biological efficiency is the ratio of fresh mushroom weight to dry substrate weight, expressed as a percentage. A 25% BE means 1 lb of dry substrate produces 0.25 lbs of mushrooms over the entire run (all flushes).

Master’s Mix typically achieves 50–100%+ BE under optimal conditions because the soy hull supplement provides additional nitrogen. Standard hardwood/bran substrates typically run 20–30% BE. Straw typically runs 25–40% BE for oyster mushrooms.

How to Check Field Capacity

Field capacity is the ideal moisture level for mushroom substrate colonization. Too wet → anaerobic conditions → contamination. Too dry → slow colonization → contamination.

The squeeze test: Take a handful of your hydrated substrate and squeeze it as hard as you can. You should see:

  • A few drops to a thin stream: Good — this is field capacity
  • No water coming out: Too dry — add water in small increments and mix
  • Steady stream of water: Too wet — allow to dry or add more dry substrate