Building a Fruiting Chamber and Managing Fresh Air
Fruiting needs a temperature drop, high humidity, fresh air, and light. Learn to build a simple chamber and balance humidity with air exchange.
What fruiting needs
Once a substrate is fully colonised, four conditions bring on mushrooms: a drop toward the species' fruiting temperature, high humidity around 85 to 95%, fresh air to clear carbon dioxide, and some light so pins form and orient.
A simple chamber
A clear storage tote makes a good first chamber.
- Drill 6 mm holes about 5 cm apart on all sides for passive air exchange.
- Add a layer of damp perlite in the base to hold humidity.
- Sit the block or tub on a rack above the perlite.
- Mist the walls and air a few times a day, and give indirect light.
Managing fresh air
Growing mycelium releases carbon dioxide, and too much gives long stems and small caps, or aborted pins. Fan or vent to swap stale air for fresh, and pair air exchange with humidity so surfaces stay damp, not wet. Oysters want frequent air, while shiitake and lion's mane tolerate more.
Scaling up
For more blocks, a grow tent with an ultrasonic humidifier on a humidistat and a small exhaust fan on a timer holds steady conditions without constant misting.