MUSHROOM 



MUSHROOM 



2083 



is able to give to his work the care and attention which 

 would be bestowed upon the cultivation of delicate 

 flowers or the rearing of poultry. 



Within the past dozen years, sufficient has been done 

 to demonstrate the fact that the general principles of 

 production are comparatively simple. The limits of 

 conditions permitting production are narrower than 

 those usually applying to other horticultural crops, 

 yet it is true that the principles in the one case are just 

 as definite as in the other. To state this in terms of its 

 causation, it may be said that many of the more 

 important biological problems concerned in the growth 

 of mushrooms are sufficiently understood to enable us 

 to comprehend the meaning and relative values of the 

 practices which have grown up about this industry, and 

 in many instances to modify these practices advan- 

 tageously. As a matter of fact, since mushrooms should 

 be grown only in situations which permit the practical 

 control of conditions that is, of the substratum or 

 compost, the amount of moisture, the temperature, and 

 other factors of the environment, it should now be, 

 and in the hands of many growers is, a more certain 

 crop than many others commonly regarded as table 

 necessities. 



It is no uncommon thing to hear the question asked, 

 "Why is it not possible to produce mushrooms suc- 

 cessfully in fields and lawns?" This question might be 

 answered by anyone who reflects for a moment on the 

 commercial success or failure of the pasture and lawn 

 occurrence of mushrooms. One could predict that 

 dandelions would be a successful lawn crop because 

 whether one wills or no they are produced on our lawns 

 in quantity, and sometimes they threaten to take pos- 

 session where they may not be wanted. Mushrooms 

 also occur in the lawn and field, but how sporadic and 

 unreliable is the supply! One expects to find them in 

 the early fall, but if they are not found, or occur hi very 

 limited quantity, it is easy to explain then- absence on 

 the ground of insufficient rain, unexpected cold weather, 

 early summer drought, or other obvious causes. This 

 merely indicates that mushrooms are not in any way 

 commercially successful in such situations. 



Mushrooms are indeed very sensitive to conditions, 

 and commercial out-of-door culture is possible only in 

 a region where the temperature conditions are fairly 

 uniform throughout a considerable period of time. 

 Moisture is not quite so important, because even in 

 the open this often may be adequately controlled. 

 Out-of-door culture is practised to a limited extent in 

 England and in France, but in no section of the world 



2408. Common commercial spawn of Agaricus campestris. 



is the common cultivated mushroom grown in the open 

 successfully to compete with the product produced in 

 mushroom -houses, cellars, or caves. Owing to the 

 overwhelming importance of the indoor culture, there- 

 fore, it is only necessary to describe this as of com- 

 mercial importance. 



It was stated above that rules may be laid down for 

 the cultivation of this crop. Rules must be in a measure 

 arbitrary if they are to be successfully applied by the 



beginner. One who has mastered the principles may 

 vary these advantageously for all changes of condi- 

 tions. The more important factors involved in mush- 

 room-growing, and about which recommendations must 

 center, maybe enumerated as follows: compost, spawn, 

 temperature, moisture, and sanitation. 



Compost. 



Stable-manure furnishes the only satisfactory com- 

 post known for commercial mushroom-growing. By a 

 suitable period of fermentation, or composting, the 



2409. Spawn of Agaricus campestris, pure culture. 



manure becomes more suitable for the growth of the 

 mushroom spawn and less likely to support the suc- 

 cession of mould fungi which would otherwise first run 

 its course. The manure should contain ample bedding 

 material. Straw, shavings, and sawdust are used for 

 this purpose; but straw is preferable from the mush- 

 room-growing viewpoint, as it not only reaches in a 

 short period of time a certain desirable stage of decom- 

 position, but good straw makes likewise a substratum of 

 excellent texture and water-holding capacity. 



When the amount of fresh stable-manure is sufficient, 

 it should be wet and somewhat packed. In a few days 

 the temperature will rise to perhaps 120 to 140 F., 

 which is indicative of an active fermentation. The 

 compost is then forked over, or "turned," care being 

 taken to mix the outer with the inner material, and 

 water is sprinkled upon it wheneyer needed to main- 

 tain the compost hi a condition which is moist through- 

 out. With straw manure, it is often sufficient to 

 "turn" three times, but a somewhat longer fermenta- 

 tion is not harmful. The turnings may be after inter- 

 vals of three to five days, the total time required for 

 fermentation in summer being from eighteen to twenty 

 days. When shavings and sawdust occur in some quan- 

 tity, a longer interval will be required. As soon as the 

 fermentation is complete the beds may be prepared, 

 as described on page 2085. 



Spawn (Figs. 2408, 2409). 



Prior to 1903 no mushroom spawn had been made in 

 the United States, the larger part of the spawn used 

 being brick spawn imported from England. French 

 flake spawn was also used to some extent. Pure cul- 

 tures derived by the tissue culture method were first 

 employed by the writer as a source of material for the 

 inoculation of bricks hi 1903. Since that tune the 

 brick spawn-making industry has become successfully 

 established in this country. In fact, the enormous 

 development of mushroom-growing within the past ten 

 years has been due more to reliable spawn and to the 

 dissemination of information explaining the growth- 

 requirements of these plants than to all other causes 

 combined. 



The percentage of failures by amateur growers has 

 steadily declined. It is not to be understood, however, 

 that all failures are due to poor spawn. Still, when one 

 hears the complaint that "the cellar was constantly at 

 a temperature between 50 and 60 F., and not a mush- 

 room appeared," one can be fairly certain that the 



