The conditions under which mushrooms may be successfully 

 grown are limited, and intelligent attention is therefore essential. 

 It must be said, moreover, that the, majority of failures may be 

 directly traced to erroneous ideas as to the cultural requisites, or to 

 a reckless disregard of conditions. The essential conditions, will 

 be subsequently defined in detail, but it may be stated here that 

 failures are usually due to one or more of the following causes: 

 (1) Poor spawn; (2) very poor manure; 3) unfavorable temper- 

 ature; and (4) heavy watering during the early stages of growth. 



Under suitable conditions mushrooms may be grown with assur- 

 ance of success. Ordinarily they are grown only where the con- 

 ditions may be controlled, and success should therefore be invariable. 



4. Temperature and Moisture 



Mushrooms may be grown in any place where the conditions of 

 temperature and moisture are favorable. A shed, cellar, cave, or 

 vacant space in a greenhouse may be utilized to advantage for this 

 purpose. The most essential factor, perhaps, is that of temper- 

 ature. The proper temperature ranges from 53 deg. to 60 deg, F., 

 with the best from 55 to 58 deg. F. It is unsafe to attempt to grow 

 mushrooms on a commercial basis, according to our present knowl- 

 edge of the subject, at a temperature much less than 50 deg. or 

 greater than 63 deg. F. Any severe changes of temperature retard 

 growth, or else act injuriously, and many changes of temperature 

 would entirely destroy the profits of the mushroom crop. From 

 this it is evident that in many places mushrooms may not be grown 

 as a summer crop. With artificial heat they may be grown almost 

 anywhere throughout the winter. Moreover, it is very probable 

 that in this country open-air culture must be limited to a few sec- 

 tions, and restricted, commercially at least, to a single season. 



It is very probable that the exact temperature which may be con- 

 sidered an optimum will vary somewhat in different sections of 

 the country. It will be noted later in detail that the temperature 

 factor acts not so directly upon the growth of the spawn or the 

 production of mushrooms as indirectly to render some other con- 

 ditions of the environment injurious. It is best to consider that 

 in practice the optimum temperature for mushroom growing varies 

 from 53 deg. to 58 deg. F. 



It was soon definitely ascertained that the conditions of pure 

 culture growth are essentially different from those attending the 

 growth of mushroom spawn in the bed. This was perhaps best in- 

 dicated by comparing spawn grown in pots at 85 deg. F. under im- 

 pure conditions with similar spawn grown at 50 deg. F. At the 

 former temperature, even though the conditions of moisture were 

 properly maintained, there was little or no growth. Foreign fungi, 

 molds, and bacteria, as well as insects, were, however, abundant. 



