growing is a cellar. It is almost incredible
how secretly the market growers guard everything in connection with
mushroom-growing from the outside world, and even from one another; in
fact, in some cases their next-door neighbors and life-long intimate
friends have never been inside their mushroom cellars.

If a cellar is to be wholly devoted to mushroom-growing it should be
made as warm as possible with double windows, and double doors, where
the entrance is from the outside, but if from another building single
doors will suffice. A chimney-like shaft or shafts rising from the
ceiling should be used as ventilators in winter, when we can not
ventilate from doors or windows; indeed, side ventilation at anytime
when the beds are in bearing condition is rather precarious. There
should be some indoor way of getting into the cellar, as by a stairway
from the building above it. Also an easy way of getting in fresh
materials for the beds, and removing the exhausted material. This is,
perhaps, best obtained by having a door that opens to the outside, or a
moderately large one from the building above.

[Illustration: FIG. 1. MUSHROOM CELLAR UNDER A BARN.]

The interior arrangement of the cellar is a matter of choice with the
grower, but the simplest way is to have beds three or four feet wide
around the inside of the walls, and beds six feet wide, with pathways
two, or two and one-half feet wide between them running parallel along
the middle of the cellar. Above these floor-beds, shelf-beds in tiers of
one, two, or three, according to the height of the cellar, may be
formed, always leaving a space of two and one-half or three feet between
the bottom of one bed and the bottom of the next. This is very
necessary, in order to admit of making and tending the beds and
gathering the crop, and emptying the beds when they are exhausted.

Provision should also be made for the artificial heating of these
cellars, and room given for the heating pipes wherever they are to run.
But wherever fire heat is used in heating these cellars, if practicable,
the furnace itself should be boxed off, by a thin brick wall, from the
main cellar, and the pipes only introduced. This does away with the dust
and noxious gas, and modifies the parching heat.

But in a snug, warm cellar, artificial heat is not absolutely necessary.
We can grow capital crops of mushrooms in such a cellar without any
furnace heat, simply by using a larger body of material in m