Some mushrooms require a composting process for industrial production, as in Agaricus species. The methods for growing Agaricus species differ from those used in growing many other mushrooms, which are grown in sawdust mixtures in bags. Agaricus is a secondary decomposer. The preparation of the substrate for growing Agaricus species is a process known as composting. Within this process, bacteria and other fungi break down the raw materials in the compost mixture, which allows Agaricus species to grow on the fermented substrate (Llarena-Herna´ndez et al. 2011). The first formal mention of mushroom cultivation based on the composting method was in 1650 in Paris. However, cultivated mushrooms were reported to be different in appearance to those harvested from the field and not as good to eat. In 1707, a French botanist reported that mushrooms were produced from horse manure covered by soil. The first record of commercial cultivation was in 1780 by a French gardener, while mushroom growing was introduced to North America after the Civil War (Beyer 2003). In 1800, the first cultivation of Agaricus in caves was achieved in Paris.

In Europe and Brazil, the basic raw material used in composting is wheat straw. hay, corncobs, oat, barley, sugarcane bagasse, rye grass, rice straw, several other grasses or spent mushroom waste can act as alternative substrates (Royse and Chalupa 2009; Stamets and Chilton 1983; Mendonc¸a et al. 2005; Llarena-Herna´ndez et al. 2011, 2014; Grimm and Wo¨sten 2018). Supplements such as soybean meal and cereal bran mixed with minerals or vitamins are added for cultivation of Agaricus and Pleurotus mushrooms (Carrasco et al. 2018). There are normally two phases in composting. Phase I is called composting, which involves mixing the piled-up ingredients. Supplements are added to the watered stack and this is incubated for 3–15 days. The temperature inside the compost stack can reach 70–80 °C, and thermophilic microbes in the compost utilize carbohydrates and free ammonia. After fermentation, the compost is pasteurized at 60 °C. Phase II is called conditioning, at which point the temperature is maintained at 45–60 °C for the culturing of good microbes, and to decrease the ammonium level of the compost (Mendonc¸a et al. 2005; Stamets and Chilton 1983; Grimm and Wo¨sten 2018).

In Asia composting has been modified as wheat straw and horse manure are not readily available. Chopped rice straw is used as the main substrate. The rice straw is supplemented with rice bran, urea, ammonium phosphate,calcium sulfate to increase nutrients. Gypsum and calcium carbonate are added for buffering the pH. The process occurs outdoors. For pasteurization, the compost is heated to 55–60 °C for 3–6 h with steam (Royal project’s method, unpublished data). When the compost is generally used and inoculated with spawn. After the mycelium runs through the compost the casing is covered to stimulate fruit-body production (Llarena-Herna´ndez et al. 2013). Different mixtures are used for casing inclduding soil: wood, charcoal: calcitic lime (Zied et al. 2010), soil: sand mixed with peat (Mendonc¸a et al. 2005) limestone: peat: thin sand (Llarena-Herna´ndez et al. 2014) after casing. Then, the mycelium grows within the casing layer in about 15–20 days depending on environmental factors, Agaricus requires around 20–30 days (Mendonc¸a et al. 2005).

Methods of cultivation have been developed that use local agricultural waste as the main substrate, instead of wheat or rice straw. Specific media need to be established for the production of fruit-bodies depending on the species of mushroom.