Conditions for Growing Mushrooms

Light

• Mushrooms do not require light for growth. Because they lack chlorophyll, photosynthesis (the process in which chlorophyll converts sunlight to energy) cannot feed a mushroom. Instead, mushrooms require decaying organic material. This means they should be kept in a very humid environment that is not too hot, as hot dry air can cause evaporation and slow decay. Mushrooms, therefore, are usually kept in a dark or shaded area. This can be indoors, under a log or in a damp forest. Overall, direct sun exposure should be avoided; it will not help mushrooms grow and may kill them.

Moisture

• The amount of moisture needed in a mushroom's growing environment can change depending on the type of mushroom and its current growth stage. However, all mushrooms require moist environments to thrive. Create an environment that allows you good control over the humidity, particularly during the spawning stage when mushrooms tend to like high humidity and low air exchange.

Substrate

• The substrate is the soil or surface on which mushrooms grow. Because they derive all of their energy from this substrate, it must be rich in organic material. Depending on the type of mushroom, substrate can take different forms. Shiitake mushrooms, for example, prefer to grow on decaying logs or sawdust. You can create a mushroom "compost" or purchase one at a garden center. Horse manure is a common ingredient, as are corn cobs. Substrate needs to be sterilized and contain a good balance of nitrogen and other nutrients.

Air

• Ideally, you should create a controlled environment for the initial stages of mushroom growing so that you can restrict air flow. Air needs vary based on the type of mushroom, but as a general rule, a high level of carbon dioxide can help mushrooms spawn. Once spawning is complete and fruiting (visible growth) begins, mushrooms should have well-ventilated air. Some types of mushrooms grow well on the underside of a rounded log, where the curved shape keeps them shaded and cool while allowing air flow. Research the air needs of your mushroom species before you begin growing.

Considerations

• Oyster mushrooms, a very common type of mushroom grown at home, can cause allergic reactions in some people. Growing mushrooms in a controlled environment, you are almost certain to be exposed to its spores. If you don't know whether you are allergic, wear protective gear or take an allergy test before growing oyster mushrooms.