Mushroom Culture

Cultivation technique

A . Filling:

The compost is filled in wooden trays or shelves or in polythene bags at different rates. The hard-compressed bags / beds attain more compost as compared to slightly compressed bags. The dry weight of substrate per square foot of cropping surface largely determines total yield. During summer the compost is slightly pressed while filling so that due to the metabolism of the growing mycelium, bed temperature may not rise as enough of heat is generated during that period. Similarly it is hard-pressed during winter season. Nutrients from the farthest point of the compost bed are transported to the growing mushroom mycelium. Filling of the trays / bags 6-8 inches deep with compost, stacking them closely, with their upper end covered with polythene or newspaper in a closed room, has been found to provide conditions for efficient spawn run and the heat generated can be managed easily. Moreover, it will add to the ideal temperature ( 25±1º C ) required for rapid colonization of the compost with mycelium.

B .SPAWNING AND SPAWN RUNNING :
a) Spawning: Mixing the mushroom seed or spawn in the compost is called as spawning. There are different methods of spawning which are as follows:

1. Surface spawning: Grain spawn is scattered all over the surface of the compost in trays or racks which is then covered with 2 cm thin layer of compost.
2. Double layer spawning: Usually done under unfavourable environmental conditions at low temperature. The trays are half filled with compost, spawn is scattered over it, then trays are filled completely with compost and again spawned in the same manner. Finally a thin layer of compost is spread on the spawn covering it completely.
3. Through spawning: The desired quantity of spawn is mixed thoroughly in the required quantity of compost which is then filled in racks, trays or bags. This type of spawning is done mainly in bag cultivation.
4. Spot spawning: Trays are filled with compost. Spawning is done in 1-2 inches deep hole made in the compost about 4-5 inches apart in rows. A tea spoonful spawn is filled in the holes which are later covered with compost. After spawning, trays or racks are covered with old newspaper sheets and watered lightly with the help of water sprayer. In Polythene bag cultivation, its mouth is tied with the help of thread.
5. Active spawning: Here in place of grain spawn, fresh compost after complete colonization by mushroom mycelium is used as spawn. In this method spawn run is very quick but care should be taken to avoid use of contaminated compost.

b)Spawn running:

The temperature of the mushroom house, where trays or bags are kept for incubation should be maintained between 22-25°C. The humidity should remain at 80-85% RH level. This can be maintained by frequently spraying water on walls and floor of the mushroom house. During spawn running , fresh air is not required, hence room should be kept closed to create darkness. Higher CO₂ concentration than the normal level in the air favours mycelial growth of the mushroom. Under favourable environmental conditions within 14-15 days of spawning, the compost surface is covered with the cottony growth of the white mycelium. This condition is called spawn run. If temperature is lower than optimum level, it prolongs the spawn run period even up to 22 days while higher temperature retards mycelial growth.

Fig. 6.1 Pasteurized compost filled in polythene bags after spawning and
kept in the spawn running room on the shelves for spawn run.

c) Supplementation at spawning:

In order to get additional increase in yield, some selected nutrients are added in the compost at the time of spawning. They are designed to become available to the mushroom mycelium during the early flushes. These supplements are specially formulated nutrients encapsulated in a denatured protein coat.The application rate is 5-7 % of the dry weight of the substrate. One has to be careful as these materials enrich the substrate, making it more suitable to contaminants, if factors predisposing to their growth are present.These type of supplements may cause 5-10 per cent increase in yield.