Mushroom Compost or Mushroom Soil as it is sometimes called is made up of a mix of organic matter. The main ingredients are shredded wheat hay, horse manure, cottonseed meal, cocoa shells, corn cobs, gypsum, chicken manure, sphagnum peat moss, ground limestone, and other decaying organic matter. These compost ingredients have very low levels of heavy metals making this an ideal soil additive. Because it is composted and pasturized to temperatures exceeding 160 degrees the heat kills any weed seeds that may be introduced with the manure.
Our mushroom compost comes from the south-eastern part of Pennsylvania near a town called Kennett Square. This area of Pennsylvania accounts for half of the mushrooms grown in the U.S. Mushrooms feed on decaying organic matter and this is the going medium they are grown in. The compost is brought into window-less cinder block buildings, placed in growing trays, and then combined with mushroom spores. Once the mushrooms are havrvested the compost is sold to garden centers all over the Eastern U.S.