Use additive-free hardwood pellets. Hydrate them into sawdust, optionally blend 1:1 with soybean hulls for the Masters Mix, then sterilise (not just pasteurise) because the added nutrition invites contaminants. Inoculate with grain spawn for shiitake, lion's mane, or oyster.
Why hardwood pellets work
Hardwood pellets are simply compressed hardwood sawdust — the same material premium mushroom substrate is made from, in a convenient, sterile-dry form. Crucially, they must be pure wood with no binders, oils, or accelerants.
Add water and they collapse into fine, uniform sawdust at a predictable moisture. That consistency is hard to get from raw sawdust, which varies by species and season.
A grower favourite: 50% hardwood pellets and 50% soybean hulls by dry weight, hydrated to field capacity and sterilised. The soy hulls add protein for vigorous colonisation and big yields, especially with lion's mane and oyster.
What you gain
Lab-grade consistency
Uniform particle size and moisture batch after batch — no guessing with mixed sawdust.
Clean starting point
Dry, densified pellets carry few contaminants, so a proper sterilise gives a clean block.
Species flexibility
Supports wood-lovers like shiitake and lion's mane, plus oyster — just adjust supplementation.
Building a fruiting block
- 1
Hydrate
Add water to pellets (and soy hulls if using) to reach about 58–62% moisture — field capacity, not soggy.
- 2
Bag
Fill filter-patch grow bags, leaving headspace for gas exchange.
- 3
Sterilise
Because the mix is nutritious, sterilise at 15 psi (≈121°C) for 1.5–2.5 hours, then cool fully.
- 4
Inoculate
Add grain spawn in still-air or a flow hood at 5–10% of block weight.
- 5
Colonise
Incubate at 22–25°C in the dark until the block is solid white.
- 6
Fruit
Move to fruiting conditions — light, fresh air, and high humidity for the chosen species.
