Mushroom Soil

Mushroom soil, or Spent Mushroom Substrate, is the steam pasteurized, partially composted remains of mushroom growing media after a crop of mushrooms has been harvested. While this product has some smell, it can be further composted into an odorless compost in 6 to 12 months. It can also be used directly as a mulch for vegetable gardens or flower beds. Do not use mushroom soil around woody shrubs that prefer acidic soil.