Spent Mushroom Compost
An alkaline compost used for amelioration and or mulching.
Spent mushroom compost is the residual compost waste generated by the mushroom production industry. It is an excellent source of humus, although much of its nitrogen content will have been used up by the composting and growing mushrooms. It remains, however, a good source of general nutrients as well as a useful soil conditioner. However, due to its chalk content, it may be alkaline, and should not be used on acid-loving plants, nor should it be applied too frequently, as it will overly raise the soil's pH levels.