Mushroom growing glossary

The terms

Terms are in alphabetical order. Each one is defined from the source named under it, and where a seller uses a word its own way, we say so.

Abort

Rootlab's word for a mushroom that fails to develop. It says aborts come from low humidity, insufficient airflow or improper lighting, and North Spore says pins that stop growing usually point to low humidity. Source: North Spore, Rootlab.

Chitin

A tough material in mushrooms. North Spore says raw chitin is hard to digest, which is why it says to always cook homegrown mushrooms thoroughly. Grocycle says cooking breaks it down. Source: North Spore, Grocycle.

Cold shock

Chilling a block that is not fruiting. North Spore's booklet suggests about 40°F for up to 24 hours when a block shows no growth. Source: North Spore booklet.

Colonization

The second of the four stages in a mushroom's life cycle, when the mycelium grows through its food. A kit arrives ready to fruit, so this stage is already done. Source: Mycologic, Host Defense.

Flush

One wave of mushrooms from a block. North Spore guarantees the first flush of its Spray & Grow kits and says up to five are possible, with later flushes usually smaller. Source: North Spore.

Fruiting body

The mushroom you eat. Hamburg University of Technology compares it to a plant's fruit, and says the spores form in gills or pores. Source: Hamburg University of Technology.

Fruiting chamber

An enclosed space that holds humidity and fresh air while a block fruits. North Spore names the monotub and the Martha tent as examples. Source: North Spore.

Grain spawn

Grain colonized by mycelium. North Spore says it is not an all-in-one kit and has to be mixed with bulk substrate before it can fruit. Source: North Spore.

Humidity tent

A trash bag with half-inch holes draped over a kit and misted inside daily, removed once pins form. North Spore suggests one for dry climates or when the AC is on. Source: North Spore.

Martha tent

A zippered tent over shelving, used as a fruiting chamber. North Spore sells its BoomRoom II as an automated Martha tent. Source: North Spore.

Monotub

A tub used as a fruiting chamber. North Spore's Boomr Bin is a monotub with an automated fan and humidifier. Source: North Spore.

Mycelial exudate

The amber beads that can appear on a block. North Spore says they are harmless. Source: North Spore.

Mycelium

The main body of a fungus. North Spore compares the mushroom to an apple and the mycelium to the tree. The Australian National Botanic Gardens says mycelium grown from a single spore generally will not produce fruiting bodies. Source: North Spore, Australian National Botanic Gardens.

Pins

The first tiny mushrooms on a block. North Spore says pinning typically begins 6 to 10 days after you activate a Spray & Grow kit. Source: North Spore.

Popcorning

Bumpy, nodular lumps on a sawdust block, described by one food-forest writer as appearing before pinning. Seller documentation does not define it. Source: Gavin Mounsey.

Primordia

The booklet's word for the early stage when mushrooms are just beginning to form. It lists a different humidity for primordia than for the fruiting body. Source: North Spore booklet.

Spore

Hamburg University of Technology says spores form in the gills or pores of the fruiting body, which is where a mushroom releases them from. Source: Hamburg University of Technology.

Spore germination

The first of the four life cycle stages, when a spore starts to grow. Source: Mycologic, Host Defense.

Sporulation

The fourth life cycle stage, when the mushroom releases spores. Harvesting oysters while the cap edges are still curled under limits spore release, per Grocycle. Source: Mycologic, Host Defense, Grocycle.

Substrate

The material a mushroom grows on and feeds from, such as logs, wood chips, straw or sawdust, according to Cornell's small farms program. Source: Cornell.

Trichoderma

A green mold. North Spore says shiitake blocks can be prone to it and suggests spraying affected areas with 3% hydrogen peroxide. Source: North Spore.

Where to go next

See how to grow mushrooms at home for these terms in use, what is mycelium for the biology, and the mushroom life cycle for the four stages.