The Monotub Method Explained
substratefruitingintermediate
A monotub colonises and fruits bulk substrate in one clear tub. A practical guide to setting up, fruiting, and keeping a monotub clean.
What a monotub is
A monotub is a large clear tub used to colonise and fruit bulk substrate in one container. It is a popular low-cost method for beginners because it holds humidity well and needs little equipment.
Setting one up
- Take a large clear tote and drill holes for passive fresh air, often two rows on the sides.
- Some growers line the lower band with black tape or paint to keep the substrate dark and discourage side pinning.
- Mix 1 part grain spawn into 2 to 5 parts pasteurised bulk substrate and fill the tub to a depth of 10 to 15 cm.
- Close the lid and let it colonise in the dark at 20 to 24°C.
Fruiting the tub
Once the surface is colonised, introduce light and fresh air to trigger pinning, and keep humidity high. Mist the walls rather than the substrate, and fan for fresh air. Harvest each flush, then rehydrate and rest the bed for the next one.
Keeping it clean
Monotubs work best with well-colonised spawn and clean substrate. A high spawn ratio helps the mycelium outrun contaminants in the open tub.