Mushroom Monotubs

Mushroom Monotubs: How They Work

A monotub is a large lidded plastic tub adapted into a self-contained fruiting chamber. Holes cut into the sides (covered with filter tape or stuffed with polyfill) give the growing mushrooms the passive fresh-air exchange they need, while the moist bulk substrate inside keeps humidity high. Because a monotub holds far more substrate and exposes a much larger fruiting surface than an all-in-one bag or jar, it produces bigger, more repeatable flushes, which is why it is the go-to setup once a grower moves past their first grow.

Our mushroom monotubs come ready to run, so you can skip drilling and taping a storage tote yourself. Fill one with colonized grain spawn mixed into pasteurized bulk substrate, and the tub handles airflow and humidity for you. New growers who want the simplest possible start can compare a monotub with an all-in-one grow bag, which trades yield for fewer steps.

To run a monotub, spawn your colonized grain into hydrated bulk substrate at roughly one part spawn to two to four parts substrate, level it in the tub, and cover it while the mycelium knits the surface together. Once the substrate is fully colonized, remove the cover or introduce light and fresh air to trigger pinning. Mushrooms then fruit from the exposed surface over several flushes, with a light misting as needed to keep the surface from drying. Keeping the tub out of direct sun and away from big temperature swings gives the most even pinning.

Monotubs suit a wide range of gourmet and functional species. Wood-lovers such as lion's mane, oyster, and shiitake fruit well in bulk given the right substrate. Size your mix to your tub with the substrate calculator, and walk through colonization and fruiting parameters in our growing guides. A well-colonized spawn and a clean tub are the two things that matter most.