Mushrooms can be defined as fruiting bodies of fungi. They have no chlorophyll and therefore lack the ability to synthesize their own food.They get nutrients from supplements like wheat or rice bran. Oyster mushrooms cultivation produces organically grown health food. Oyster mushrooms cultivation is the most economical way to utilize agricultural by products which would otherwise be burned or left to rot in the field polluting the environment. The spent mushroom cultivation media can be used as compost or livestock feed. Therefore mushroom cultivation is a good environmental conservation method.Oyster mushrooms cultivation which is common in Kenya is inexpensive and has a readily available market. Oyster mushrooms cultivation can be done using readily available inexpensive substrates which include straw, sugarcane baggase, coffee residues, straw, banana waste, cotton seed hulls and sawdust. Oyster mushrooms cultivation requirements are Spawns, Substrate, and a room, Supplements like wheat or rise bran, Agricultural lime, Poly bags, string and Water.
The following are the ingredient ratios for oyster mushrooms cultivation media preparation; 1kg supplement: 4kilograms substrate: 8litres water per poly bag.75% moisture is recommended to avoid water logging.Sterile conditions are essential for oyster mushrooms cultivation; therefore preparation starts with pasteurization which involves chopping of the substrate and soaking overnight for moistening, then packing it in poly bags, followed by submerging the poly bags for 2 hours in boiling water at 90ºC and above, and then cool the bags for 24-48 hours.
Bleach method is an alternative sterilization method in oyster mushrooms cultivation and it involves the use of household bleach 5.25 percentage of sodium hypochlorite.5-6 cups of the bleach is added to 190 litres of water, after which the substrate is submerged for 4-12 hours. As a caution, the bleach solution which remains should be drained off where there is no vegetation to avoid scorching.
Spawning or sowing the seeds is the next step which is carried out in a dark room, followed by tying the poly bag at the top. Open after 28 days while white colonies start appearing. Open the top of the bag only to avoid sprouting from several surfaces which might lead to a glut leading to marketing problem. 3 days after opening the bags, white pin heads appear and water spray should be done to facilitate pinheads opening. Damp conditions are critically required at this point of oyster mushrooms cultivation and hence earth floors should be should be sprinkled with water while cemented floors are covered with a damp Hessian Cloth. Harvesting starts 30-40 days after spawning or sowing and optimal cropping cycle is 70-80 days, thus harvesting can continue for a period of 8 weeks.
The ventilation space between the wall and the roof should be minimized during construction to avoid excess moisture loss or adapted if an already constructed structure is used. The shelves which hold the poly bags should be made on double rows in order to allow space for watering and harvesting. The shelves should be 1 metre wide while the lowest shelf should be 15 cm from above ground.
