418 VEGETABLE FORCING 



Fig. 153. A good crop of mushrooms. 



rooms. Growth is more rapid at higher temperatures, 

 but the period of production is shorter and the crop 

 lighter. Fair results are possible at 60 to 65 degrees, and 

 satisfactory yields may be obtained when the tempera- 

 ture is about 50 degrees. Low temperatures invariably 

 prolong the period of production. The maintenance of 

 proper temperatures is the most important means of con- 

 trolling insects and diseases. 



Light. Light is not injurious to the growth of mush- 

 rooms, for, as previously stated, they are often grown 

 under the benches in greenhouses and in cellars provided 

 with windows without any attempt to screen the beds 

 from light. It is indeed an advantage to have some day- 

 light in mushroom houses, though artificial lights are 

 generally employed. Large windows are objectionable 

 because they admit sunlight and this may raise the 

 temperature of the house at a time when additional heat 

 would be disastrous to the crop. 



Insect enemies may appear in mushroom houses, 

 but they seldom cause serious losses when proper 

 sanitary measures are observed. It is very impor- 

 tant, however, for growers to be alert, for insect 



