White button mushrooms are one of the most common mushrooms in grocery stores and in recipes. They are also one of the easiest mushrooms to grow at home, requiring little in the way of ongoing maintenance. They can be grown from kits that can be purchased on the Internet. However, they are easy enough to grow directly from spawn, so most home growers choose this method.
Fill the plastic bin with the composted manure to a depth of 3 inches. Keep the compost light and fluffy and do not pack down with your hand.
Place the bin in a dark, warm area such as a basement shelf or under the kitchen sink. The area should be out of the main flow of household traffic and should stay a consistent temperature. Lightly mist the surface of the compost with a plant water sprayer.
Set the bin on top of a heating pad if the ambient temperature of the growing area is less than 70 degrees F. Adjust the heating pad control until the temperature at soil level is 70 degrees.
Sprinkle the white button mushroom spawn evenly over the surface of the compost. The package will state how much of an area the contents will cover. Adjust for the size of your bin. For example, if the package holds enough spawn for 20 square feet and your bin is 5 square feet, use only 1/4 of the package. Close up the remainder in the bag so that it does not dry out. Do not cover the planted spawn with compost.
Wait approximately three weeks for the mushroom spawn to begin to grow. New growth will look like tiny bubbles on the surface of soil. As they grow, they will look more like mature button mushrooms with a white dome and short stalk. When the spawn have begun to show signs of growth, place the bin in a dark area with a temperature of between 50 and 55 degrees F to continue growth.
Harvest the mushrooms beginning at the two-month mark. Harvest the largest mushrooms by slicing carefully at soil level with a sharp paring knife. The remaining mushrooms will continue to grow as will new ones and there will be several flushes of mushrooms over several months.
Dispose of the compost in the bin when mushroom production slows significantly. In warmer climates, dumping the compost under a deck or porch may result in another flush of mushrooms outside in spring. Sterilize the bin with bleach and water in preparation for another batch of mushrooms.