Spawn is the living fungal culture, called mycelium, grown onto a substrate. It provides the backbone to any mushroom growing operation. Think of it as the equivalent of seeds for a mushroom farm. Unlike seeds, though, mushroom spawn is grown from selected genetics and cloned for consistent production of a particular cultivar of mushroom. This is similar to how people grow apples from grafted wood as opposed to planting apple seeds. Grafting ensures that a particular selected set of genetics produces a consistently delicious apple variety. Seeds (and spores for that matter!) are a genetic grab-bag dependent on two individual sets of genetic material, while spawn is a single genetic culture that can be propagated indefinitely from the same 'master'. The 'master' cultures are kept on agar petri dishes in our laboratory.
