The inoculation or the culture room for tissue culture was also shown to us. This room should be about 2.25 m in height and 1.25 m in length. Two tubes i.e. an ultra-violet tube and a normal tube light are used. A spirit lamp is also used. One can produce up to six generations from one bottle of mother spawn with the help of tissue culture. After six generations the strength of the spawn decreases and the yield of the mushrooms will be less.
Substratum: Paddy straw is the main substratum used for growing mushrooms-it contains cellulose and lignin, both of which are necessary for the growth of mushrooms. However many other kinds of substrata are also used, for example, saw dust, sacks, banana leaves, dry mango leaves, coconut leaves, sugarcane, wild grass, rice husk, etc.
The paddy straw must be carefully selected. It should be brittle, yellow or golden brown in colour and not older than 6 months. The straw should be dried in the sun for several days, stored if necessary in an air-tight container and used within two months. The ratio of paddy straw to mushroom spawn should be 1 kg "prepared" straw to 4% spawn.
Procedure: First the straw must be prepared. The straw should be cut to 3-5 cm pieces. It should then be filled in cloth bags and soaked in water (1 kg straw to 10 litres water) for 10 hours. The straw should be weighted down in the water so that no part of it remains above the level of water.
The next stage is pasteurization. Water must be boiled to a temperature of 80 to 85oC. When bubbles appear, the soaked straw, surrounded by the cloth bags, should be weighted down and fully immersed in water. The bubbles will disappear when the straw is immersed and then reappear. Thirty minutes after the reappearance of bubbles the straw should be removed. It should be drained of water and cooled at room temperature, then spread out on a clean surface and dried for two hours.
The moisture content of the straw should not exceed 60%. To judge the moisture content one should hold some straw between one's fingers and squeeze tightly. If only one drop of water comes out, then the moisture content is correct.
Polythene or polypropylene bags are now required to fill the straw into. The bags should be approximately 35 x 50 cm and should weigh 150 gms each. Before using them, they should be washed with savlon or dettol or formalin. Four strings should be tied together at one end which should be placed at the bottom of the bag. The four free ends must be held outside the bag. The bag can now be filled. First a 5 cm layer of straw should be put in and the straw pressed lightly against the bottom. Mushroom spawn should then be spread over it. Then another 10 cm layer of straw, over which the spawn should be spread and so on till one reaches the top of the bag. Finally it must be covered with a final 5 cm layer of straw, and the four pieces of string and the bag must be tied together. The bags can either be kept on the ground or hung in the room. Hanging them enables one to get at the mushrooms from the bottom of the bag easily.
The following day, 30 to 35 holes should be made in each bag with a sterile needle. The bags should be kept in darkness, with very little ventilation allowed to them, for 15 days. The bags should then be moved to another room. Here they should get four hours of diffused light and cross ventilation. After one and a half days the substrate should be sprayed with water three times a day with a shower pointing upwards so that the water falls on the bags like rain. On the following day small mushrooms, the size of pinheads will appear. Two days later fully grown mushrooms will appear. The mushrooms should not be pulled out because the substrata will also be pulled out with it. Instead they should be cut or twisted and broken off from the base. If the substrata is dry the bag should be given a quick dip in water. Otherwise continue spraying with water. The second crop of mushrooms will reappear one week later. The process can be continued upto 4 times. Then one has to start afresh. This is because after 4 crops the substrata begin to attract disease and get contaminated.
Pests and Diseases: Mushrooms are easily attacked by pests and diseases and therefore require utmost care and good management. Of the two well known types of mushrooms, the button mushroom is more prone to disease whereas the oyster mushroom is hardier.
Insects which attack mushrooms are the Scearid fly, the Phosid fly, Spring Tails (small insects like grasshoppers) and mites. To prevent insects from attacking mushrooms it is best to keep the mushroom bags at least one foot above the ground. One can burn sulphur in the room before seeding the mushrooms. Citronella oil mixed with water can also be used for spraying on the bags. It is absolutely essential to maintain the highest standards of hygiene to prevent attack by insects.