llustration: FIG. 18. BANKED BED AGAINST A WALL.]

In open, airy greenhouses it is always well to inclose the mushroom beds
in box casings and with sash or shutter coverings, to prevent draughts
and fluctuations of temperature and atmospheric moisture. This can
easily be done by making the sides a board and a half (fifteen inches),
or two boards (twenty inches) high, and covering over with light wooden
shutters, sashes, or muslin or paper-covered light frames. See Fig. 11.

=Ammonia Arising.=--Ammonia arising from the manure of the mushroom beds
in the greenhouse may be injurious to the other inmates of the
greenhouse. If the manure has been well prepared before it was
introduced into the greenhouse, the ammonia arising from it will not, in
the least degree, injure any other plants or flowers that may be in the
house; but if the manure is fresh, hot, and rank, the opposite will be
the case. Beds in greenhouses should always be made up of manure that
has been well prepared beforehand out of doors or in a shed, and as it
is brought into the greenhouse it should at once be built solidly into
the beds. Then very little steam will arise from the beds; in fact, it
will be imperceptible to sight or smell.

CHAPTER VI.

GROWING MUSHROOMS IN THE FIELDS.

Under suitable conditions we can grow mushrooms easily and abundantly in
the open fields, and the planting of the spawn is all the trouble they
will cause us. During the late summer and fall months mushrooms often
appear spontaneously and in great quantity in our open pastures, but in
their natural condition they are an uncertain crop, as in one year they
may occur in the greatest abundance, and in the next perhaps none can be
found in the fields in which they had been so numerous the previous
year. Why this should be so is not very clear. The popular opinion is
that after a dry summer mushrooms abound in the fields, but after a wet
summer they are a very scarce crop; and the inference is that the
moisture has killed the spawn in the ground. This may be true to a
certain extent, but how does it happen--as it certainly often does--that
good spawn planted by hand in the fields in early summer will produce
mushrooms toward fall no matter whether the summer has been wet or dry?
At the same time, it is true that a wet spell immediately succeeding the
planting of the spawn will kill a great deal of it.

As a rule, wild mushrooms abound most in rich, old, well-drained,
ro