At Fungi Perfecti, mushroom propagation begins in a clean-room laboratory equipped with airlocks, laminar-flow hoods and other devices to prevent contamination by airborne mold spores or bacteria. After mushroom spores or bits of tissue are placed in petri dishes full of agar (shown here), threads of mycelia will gradually spread throughout the substrate.
Once a culture is established, it can be used to inoculate a growing medium known as spawn, which can be made from sawdust, rice, damp cardboard or other fungus-friendly material. Small quantities of mushrooms may be grown directly from spawn, in bags or pots. Spawn can be mixed with a bulkier substrate, such as wood chips or straw, to cover a larger area. In this way, the mycelium from a single petri dish can be cultivated to help provide food or medicine for thousands of people, or remove pollutants from soil or water.