What is Mushroom Spawn?

Mushroom spawn refers to the vegetative growth or mycelium of fungi that are cultivated to produce edible mushrooms. It is the starting material used in mushroom cultivation, similar to a seed in plant propagation. Mushroom spawn is made by growing mushroom spores or tissue culture in a nutrient-rich medium until they form a web-like network of threads known as mycelium as pictured above.

The mycelium of the mushroom spawn is then mixed with a substrate, such as compost or sawdust, which provides the nutrients needed for the mycelium to grow and eventually form fruiting bodies or mushrooms. The mycelium colonises the substrate, breaking down the organic matter and creating a suitable environment for the growth of the mushrooms.

Spawn is typically sold in three forms: grain spawn, sawdust spawn, and plug spawn. Grain spawn is made by growing mycelium on sterilised grains like rye or millet, while sawdust spawn is made by growing mycelium on sterilised sawdust, and plug spawn (sometimes called dowel spawn) is made by growing mycelium on wooden dowel pins. The choice of spawn type depends on the type of mushroom being cultivated, the substrate being used, and the specific requirements of the cultivator.

Overall, mushroom spawn is a crucial component of mushroom cultivation, providing the necessary starting material for growing edible mushrooms both indoors and outdoors.