The proper temperature.

The best temperature at which to keep the mushroom house or cellar is 55 deg. to 57 deg.. But much depends upon the method of growing the esculent; the construction of the house or cellar, and other circumstances. Mushrooms can be successfully grown in buildings in which the temperature may be as low as 20 deg. or as high as 65 deg.. By covering the beds well with hay or other protecting material they can be kept warm, even in sharp frosty weather, as the London market gardeners do with their outdoor beds in winter; but when the temperature in the structure in which the mushrooms are grown averages as high as 70 deg. we can not hope for success; indeed, 65 deg. is too high.

A high temperature in a close house or cellar is injurious; it hurries in the crop and forces up the mushrooms weak and thin-fleshed and with ungainly, long stems; it soon exhausts the bed. The time when its evil effects are least visible is early in the fall and late in spring when the outside temperature is high, and when the beds are in somewhat airy rather than close quarters. In the Dosoris cellars there is a steady difference of about 5 deg. in the temperature between the end next the boiler, which is kept at 60 deg. precisely, and that of the farther end, which registers 55 deg. steadily. There is very little difference in the weight of crop produced on the beds at either end of these cellars, but what little there is is in favor of the cooler end. At 60 deg. the crop begins to come in in six to seven weeks after spawning, lasts for three to four weeks in heavy bearing and a week or more longer in light bearing, and then it gradually dwindles.

In a temperature of 55 deg. it may be seven weeks after spawning before the mushrooms appear. In a temperature of 50 deg. they may take a few days longer in appearing, but, as a rule, they are firm, heavy, short-stemmed, and perhaps a little furry on top and clammy to the touch, and the beds last in good bearing for two months; indeed, often a whole winter long. But I have failed to find that the whole crop from a bed in a 45 deg. to 50 deg. temperature was any greater than that of a like bed in a 55 deg. to 57 deg. temperature; it is merely a case of getting in six weeks from the warmer house what it takes ten weeks to get from the cooler one.

In a temperature of 50 deg. it is not necessary to cover the beds to increase their warmth, nor is it needful even in one of 45 deg., if there is a fair warmth in the body of the bed to keep the spawn working; but if the warmth of the interior of the bed falls under 57 deg., and the atmospheric temperature under 45 deg., the bed should be kept warm by covering with hay, straw, matting, or other material, or better still by boxing it over and laying this covering on the outside of the boxing. When cold thicken the covering, when warm lessen it.