In the wild, mushrooms grow on both soil and other substrates like wood, but no soil is necessary for growing them at home.
Use 14x16-inch trays about six inches deep that resemble seed flats. Fill the trays with the mushroom compost material and sprinkle spawn on top.
Use a heating pad to raise the soil temperature to around 70°F for about three weeks or until you see the mycelium (white, threadlike growths).
Keep the soil moist by spritzing it with water and covering it with a damp cloth, making sure that you keep spritzing the cloth as it dries.
Button mushrooms should appear within three to four weeks. Harvest them when the caps open, and the stalk can be cut with a sharp knife from the stem.