BUTTON MUSHROOM
The cultivated mushroom is grown on special composts, which are of the following two types, synthetic and natural.
Composting yard
The
 compost should be prepared on well cleaned concrete or pucca floor,  
which should be at a higher level so that the run-off water does not  
collect near the heap.Composting is usually done in the open, but it has
  to be protected from rain by covering it with polythene sheet. It can 
 also be done in a shed with open sides or a large room to shelter it  
from rain.
1. Synthetic compost
The following ingredients are required for 15-16 trays of size 100cmx50cmx15cm:-
Wheat
 straw (chopped 8-20cm long)-250kg, Wheat/rice bran-20kg, Ammonium  
sulphate/calcium ammonium nitrate-3 kg, Urea-3kg, Gypsum-20kg
The
 straw is uniformly spread over the compo sting yard in a thin layer  
and wetted thoroughly by sprinkling water. All ingredients such as wheat
  bran, fertilizers, etc. except gypsum, are mixed thoroughly in the  
wetted straw, which is finally heaped into a pile. The pile, 1m high, 1m
  wide and length adjustable, can be made with hand or stack mould. The 
 straw should be firmly but not compactly compressed into the mould.
It is essential to open the entire pile and remake it a number of times according to the following schedule:
Mixing of material and making pile - 0 day
1st turning - 4th day
2nd turning - 8th day
3rd turning - 12th day, add 10 kg gypsum
4th turning - 16th day, add 10 kg gypsum
Final
 turning - 20th day,spray 10 ml malathion in 5 litre water (any  other 
available pesticide like DOT, BHC, lindane can also be used)
At
 each turning water should be sprinkled to make up the loss of water  
due to evaporation. If it is desired to add molasses, then 10 kg  
molasses diluted 20 times with water should be poured over the straw  
mixture during the first turning. Sixty kg chicken manure, if available,
  can also be added at the time of start of pile.
2. Natural compost
The following ingredients are required for 15-16 trays of size 100cmx50cmx15cm:-
Horse dung-1000kg, Chopped wheat straw-300 to 350kg, Gypsum-25kg Poultry manure-100 to 110kg (or 3kg urea).
It
 is prepared from pure horse dung (dung of other animals should not be  
admixed), which must be freshly collected and should not have been  
exposed to rain. Chopped wheat straw is mixed with horse dung, urea or  
poultry manure. The mixture is uniformly spread over the compo sting  
yard and water is sprinkled over it so that the straw becomes  
sufficiently wet. The manure is then heaped in a pile as for synthetic  
compost. After 3 days when the manure in the heap gets heated up due to 
 fermentation and gives off an odour of ammonia it is opened. The 
process  is repeated 3 or 4 times after an interval of 3-4 days. Twenty 
five kg  gypsum per tonne is added in two instalments at the 3rd and 4th
 turning.  At the final turning 10 ml malathion diluted in 5 litres of 
water is  sprayed into the manure.
Compost Filling in trays:
The
 compost when ready for fil1ing and spawning has a dark brown colour  
and no trace of ammonia. There is no unpleasant odour but it smells like
  fresh hay. The pH is neutral or near neutral. The compost should not 
be  too dry or too wet at the time of filling in the trays, which can be
  determined by the palm test. For this purpose a small quantity of  
compost is taken into the hand and pressed lightly, if a few drops of  
water ooze out of the fingers then it is of right consistency. If  
relatively dry then the water should be made up by sprinkling. If too  
wet, the excess water should be allowed to evaporate. The prepared  
compost is now filled in trays, which may be of any convenient size but 
 depth should be 15-18 cm. A standard size of tray is 100 cm x 50 cm x 
15  cm. The trays should be made of soft wood and provided with the pegs
 at  the four corners so that they can be stacked one over the other 
leaving  sufficient space (15 cm) between the two trays for various 
operations.  The trays are completely filled with the compost, lightly 
compressed and  the surface levelled.
Spawning
Spawning
 means sowing the beds with the mycelium (spawn) of the  mushroom. Spawn
 can be obtained from Mushroom Laboratory, Y. S. Parmar  University, 
Chambaghat, Solan; National Mushroom Research and Training  Centre, 
Chambaghat, Solan (H.P.) at a nominal cost. Small quantity of  spawn is 
also available from the Division of Mycology and Plant  Pathology, 
Indian Agricultural Research Institute, New Delhi. The grain  spawn is 
scattered on the surface of the tray bed which is covered with a  thin 
layer of compost. Spawning can also be done by mixing the spawn  with 
compost before filling it in trays. Five hundred gram spawn is  
sufficient for five trays of standard size. After spawning, the compost 
 surface is covered with old newspaper sheets, which are wetted by  
sprinkling water to provide humidity but no water is directly added to  
the compost during spawn running.
The trays after 
spawning are stacked vertically one over the other in  4-5 tiers. One 
metre clear space may be left in between the top tray and  ceiling. 
There should be about 15-20 cm space between the two trays.
The
 room should be maintained around 25°c. The humidity should be built  up
 by frequently watering the floor and walls. The room may be kept  
closed as no fresh air is needed during the spawn run. White cottony  
mycelium spreads and permeates through the compost. Eventually the  
compost surface gets covered with the mycelium. It takes 12-15 days for 
 complete spawn run. Low temperature prolongs the spread of the 
mycelium.  
Casing
After the spawn run is 
complete as is evident by white cottony growth,  the surface of the 
compost is covered with 3 em layer of casing soil. A  suitable casing 
soil can be prepared by mixing equal parts of well  rotten cowdung 
(finely crushed and coarsely sieved) and garden soil. The  casing 
material should possess high water holding capacity, good pore  space 
and pH should not be lower than 7.4. The casing material is  sterilized 
to kill insects, nematodes and molds. Sterilization can be  accomplished
 either by steaming or by treating with formalin solution.  For one 
cubic metre of casing soil, hqlf litre for formalin (40%)  diluted with 
10 litre of water is sufficient. The casing soil is spread  over a 
plastic sheet and treated with formalin by sprinkling. The  treated soil
 is piled up in a heap and covered with another plastic  sheet for 48 
hours. The soil is turned frequently for about a week to  remove all 
traces of formalin which can be tested by smelling. After  casing, the 
temperature of the room is maintained at 25°C for further  three days, 
after which it must be lowered to below 18°C. At this stage  lot of 
fresh air is needed and, therefore, the growing room should be  
ventilated by opening windows etc.
Cropping and HalVesting
The
 first flush of the pin heads become visible 15-20 days after casing  or
 35-40 days after spawning. Small white buttons develop 5-6 days after  
pin head stage. The right stage of harvest is when the caps are still  
tight over the short stem. In case the buttons are allowed to mature  
further, the membrane below the cap will rupture and the cap will open  
up in umbrella-like shape. Such mushrooms are considered to be inferior.
 Harvesting is done by holding the cap with forefingers slightly pressed
  against the soil and twisting it off. The soil particles and mycelial 
 threads clinging to the base of the stalk are chopped off. Mushroom can
  also be harvested by cutting off with a sharp knife at soil level.
Yield
The
 average yield of 3-4 kg per tray is considered normal. However, if  
compost is carefully prepared, spawn is reliable and temperature is  
favourable, then a yield of 5-6 kg per tray is possible. Partial or  
complete failure may also happen due to negligence.
Storage
The
 mushrooms are best consumed fresh. Storage in refrigerator for a few  
days is possible if they are placed between moist paper towel.