During mushroom cultivation, compost colonized with mushroom mycelium is covered with a 3–5 cm thick casing layer which is nutritionally deficient medium to initiate the development of sporophores. Casing acts as a platform for initiation of uniform fruitification and also provides anchorage and essential reserves for developing sporophores of mushrooms. Peat moss is mainly used as casing In most of the countries but, in India, FYM + loam soil is used as casing for the production of Agaricus bisporus. Physical and chemical properties of casing like water holding capacity, porosity, bulk density, pH and electrical conductivity play very important role during mushroom production. In addition to physical and chemical parameters, microbiological parameters of the casing are also important for the proper fruiting of mushroom. Additionally, if already spawn run compost is added to casing, it increases the yield.
