THE PROPER TEMPERATURE.
The best temperature at which to keep the mushroom house or cellar is
55° to 57°. 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° or as high as 65°. 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° we can not hope
for success; indeed, 65° 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° in the temperature between the end next the
boiler, which is kept at 60° precisely, and that of the farther end,
which registers 55° 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° 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° it may be seven weeks after spawning before the
mushrooms appear. In a temperature of 50° 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° to 50° temperature was any greater than that of a like bed
in a 55° to 57° 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° it is not necessary to cover the beds to
increase their warmth, nor is it needful even in one of 45°, 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°, and the
atmospheric temperature under 45°, 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.