While many American growers have been successful, a much larger number have failed. In most cases their failures have been due to one or more of the following causes:
(1) Poor spawn, or spawn which has been killed by improper storage.
(2) Spawning at a temperature injuriously high.
(3) Too much water either at the time of spawning or later.
(4) Unfavorable temperature during the growing period. It is therefore important to the prospective grower that careful attention be given to the general discussion of conditions which follow.
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 temperature. The proper temperature ranges from 53 degree to 60 degree F., with the best from 55 degree to 58 degree F. It is unsafe to attempt to grow mushrooms on a commercial basis, according to our present knowledge of the subject, in a temperature much less than 50 degree or greater than 63 degree F.
Any severe 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 sections.
A second important factor is moisture. The place should not be very damp, or constantly dripping with water. Under such conditions successful commercial work is not possible. A place where it is possible to maintain a fairly moist condition of the atmosphere, and having such capability for ventilation as will cause at least a gradual evaporation, is necessary. With too rapid ventilation and the consequent necessity of repeated applications of water to the mushroom bed, no mushroom crop will attain the highest perfection.
Even a little iron rust in the soil is reported as fatal to the Campestris, the only fungus so far successfully propagated.
If other fungi than the Campestris come up wild, don't throw them away as worthless. Many are better eating than the one you seek, and you can avoid the risk of poisonous ones by learning to recognize the dangerous family—send for the Agricultural Department's Bulletin No. 204. Meanwhile, (1) all mushrooms with pink gills, (2) all coral-like fungi, (3) all that grow on wood, and (4) all puffballs, are good to eat if they are young and tender—only don't mistake an unspread Aminita for a puffball.