In order to get started growing your own mushrooms, you must first locate a suitable environment, either indoors or out, where you can set up your culture. The ideal environment for mushroom growing should be somewhere dark, moist and cool. Often, this turns out to be a room in the basement, although mushrooms will do just as well outdoors when conditions are met. For optimal mushroom growth, you should ensure that the ambient temperature does not fluctuate outwith 55-60°F and that your culture will be protected from drafts.

Mushrooms are cultivated by inoculating a growing medium with mycelium. Mycelium is the fungus’ vegetative growth and absorbs all the nutrients required for fungal growth, much like the root system of plants. The edible mushroom is the fungus’ fruiting structure. It contains the spores that are released in order for the fungus to reproduce.

The growing medium and method of inoculation depends on the type of mushroom you are growing. For example, Agaricus mushrooms are commonly grown in well rotted horse manure or a synthetic compost, while wood mushrooms such as shiitakes are grown on logs.

If you want to grow Agaricus mushrooms then you should obtain some fresh horse manure and mature it by composting. This process involves giving the manure a good initial watering and turning it twice weekly, watering each time you turn. The manure is ready when it has turned a rich dark brown color and can then be set into trays. The trays should be allowed to sit for one week to allow any heat to dissipate prior to inoculating.

You can purchase mushroom spawn online or from seed catalogues. For example Field and Forest (http://www.fieldforest.net/store/inde...) supply spawn in a variety of ways to suit the growing substrate. Once you have your spawn, you are ready to inoculate.

Inoculate the manure compost by planting the spawn approximately 2 inches deep, spacing the plantings 8-10 inches apart. The amount you plant will depend on the spawn you purchased so check the specific instructions that came with. To encourage the mycelium to spread, keep the culture in darkness at 70°F for 3 weeks. Once the mycelium from each planting is beginning to meet, you should drop the temperature to 60°F and cover the trays with a good quality soil. Keep the cultures moist and the first flush of mushrooms should be visible in around 3 weeks (visible as tiny white dots). These should be ready to harvest in approximately 10 days when the cap slits away from the stem.

To grow shiitakes, in addition to spawn, you will also need to acquire logs to grow in. White oak logs are popular and should be approximately 6 inches in diameter. Time from cutting to inoculation varies with geographic location. For example, in more northern latitudes, the logs should be cut in Fall and inoculated with spawn within a month. However, further South, it is best to inoculate the log within 2 weeks of cutting (see http://www.fieldforest.net/store/inde...)

Logs are inoculated by drilling holes approximately 1 inch deep into the log. A spawn plug (mycelium grown into a hardwood dowel) can then be tapped into the hole and sealed with molten wax. The wax seals the wound and acts as a barrier to other fungi or bacteria that may harm your mushroom culture. The logs should then be stacked in a shady place and soaked gently with a hose about once a week to keep the logs moist. Then sit back and wait... you should see mushrooms in a few months!

Resources
http://www.motherearthnews.com/organi...
http://pubs.cas.psu.edu/freepubs/pdfs...
http://www.hfrr.ksu.edu/doc1763.ashx