MUSHROOM GROWING 



humidity, 60 to 75 per cent, being satisfac- 

 tory. A gradual but slow evaporation from 

 the surface of the beds is altogether desira- 

 ble, and as a rule this can be easily regu- 

 lated by controlling ventilation. The un- 

 desirable extremes, so far as moisture and 

 ventilation are concerned, therefore, would 

 be on the one hand caves in which there 

 could be no circulation of air, and, on the 

 other, exposure to drying winds. The ques- 

 tion of watering the beds will be fully 

 treated in a later section (p. 75, 80). 

 Light. Since mushrooms are ordinarily 

 grown in cellars or other light-proof houses, 

 it has been assumed by many that light is an 

 injurious factor in the cultivation of this 

 fungus. A moment's thought, however, 

 would doubtless suggest that in pastures or 

 fields, where mushrooms are ordinarily 

 found, the young buttons are exposed to 

 direct light as soon as they begin to burst 

 forth through the sod. As a matter of fact, 

 light has obviously no directly injurious ef- 

 fect upon the quality or productiveness of 



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