Build a shotgun fruiting chamber
The cheap plastic box that turns colonised cakes into mushrooms.
A shotgun fruiting chamber (SGFC) is a clear plastic tub drilled full of holes, sitting on a bed of damp perlite. It holds humidity while still exchanging air, which are the two conditions fruiting needs and the two that fight each other in a sealed container.
What you need
- A clear plastic storage tub, roughly 50–60 litres, with a lid
- A drill with a 6mm (1/4") bit
- Perlite, enough for a 10cm layer
- A spray bottle
Drilling
Mark a grid roughly 5cm apart across all four sides and the lid, then drill every mark. Yes, it's a lot of holes; the chamber only works if air can drift through constantly. Sand or flame off the burrs so you don't cut yourself reaching in.
The perlite bed
Rinse the perlite, then drain it thoroughly. It should be damp to the touch with no water pooling at the bottom of the tub — standing water breeds bacteria rather than humidity. Fill to about 10cm.
Using it
Wipe the inside with 70% isopropyl before the first use. Stand your cakes on foil so they do not wick water directly from the perlite. Mist the walls and fan through the holes once or twice a day; never blast the cakes themselves.
Keep it in indirect light. Direct sun overheats a clear tub quickly.