274 STUDIES OF AMERICAN FUNGI. 



continuously. So soon as a bed has been exhausted the material is 

 cleaned out, and new beds are made as fast as the fresh manure is 

 obtained. In houses where the mushrooms cannot be grown during 

 the summer, the crops are grown at quite regular periods, the first 

 crop during fall and early winter, and the second crop during spring. 

 Some obtain the manure and ferment it during August and Septem- 

 ber, spawning the beds in September and October. Others begin 

 work on the fermentation of the manure in June or July, make up 

 the beds in July and August, spawn, and begin to draw off the crop 

 somewhat earlier. The second crop is prepared for whenever the 

 first one is drawn off, and this varies even in the experience of the 

 same grower, since the rate of the running of the spawn varies from 

 time to time. Sometimes the crop begins to come four or five weeks 

 from the time of planting the spawn. At other times it may be two 

 or three months before the spawn has run sufficiently for the crop 

 to appear. Usually the crop begins to come on well in six to eight 

 weeks. The crop usually lasts for six weeks to two months, or 

 longer. 



Productivity of the beds. One pound of mushrooms from every 

 two square feet of surface is considered a very good crop. Some- 

 times it exceeds this, the beds bearing one pound for every square 

 foot, though such a heavy yield is rare. Oftener the yield is less 

 than half a pound for a square foot of surface. 



Causes of failure. The beginner should study very carefully the 

 conditions under which he grows his crops, and if failure results, he 

 should attempt to analyze the results in the light of the directions 

 given for the curing of the manure, its moisture content, ** sweet- 

 ness," character of the spawn, temperature, ventilation, etc. While 

 there should be good ventilation, there should not be drafts of air. 

 A beginner may succeed the first time, the second or third, and then 

 may fail, and not know the cause of the failure. But given a good 

 spawn, the right moisture content of the material at time of planting 

 and running of the spawn, the sweet condition, or proper condition 

 of the curing of the manure, proper sanitary conditions, there should 

 be no failure. These are the most important conditions in mush- 

 room culture. After the spawn has run and the crop has begun to 

 come, the beds have been known to freeze up during the winter, and 

 in the spring begin and continue to bear a good crop. After the 

 spawn has run well, beds have accidentally been flooded with water 

 so that manure water would run out below, and yet come on and 

 bear as good a crop as adjoining beds. 



Volunteer mushrooms in greenhouses. Volunteer mushrooms some- 



