MAKING UP THE MUSHROOM BEDS.
The place in the cellar, shed, house, or elsewhere, where we intend to
grow the mushrooms, should be in readiness as soon as the manure has
been well prepared and is in proper condition for use. The bed or beds
should be made up at once. The thickness of the beds depends a good deal
upon circumstances, such as the quality of the manure,--whether it is
plain horse manure, or manure and loam mixed together,--or whether the
beds are to be made in heated or unheated buildings, and on the floor or
on shelves. Floor beds are generally nine to fifteen inches deep; about
nine inches in the case of manure alone, in warm quarters, and ten to
fourteen inches when manure and loam are used. In cool houses the beds
are made a few inches deeper than this so as to keep up a steady, mild
warmth for a long time. The beds may be made flat, or ridged, or like a
rounded bank against the wall; but the flat form is the commonest, and
the most convenient where shelves are also used in the same building.
Shelf beds are generally nine inches deep; that is, the depth of one
board.
In making up the beds, bring in the manure and shake it up loosely and
spread it evenly over the bed, beating it down firmly with the back of
the fork as you go along, and continue in this way until the desired
depth is attained. If it is a floor bed and there is no impediment, as
a shelf overhead, tread the manure down firmly and evenly; if the manure
is fairly dry and in good condition it will be pretty firm and still
springy, but if it is too moist and poorly prepared treading will pack
it together like wet rotten dung.
Now pierce a hole in the bed and insert a thermometer. There are
"ground" or "bottom-heat" thermometers, as gardeners call them, for this
purpose, but any common thermometer will do well enough; and after two
or three days examine this thermometer daily to see what is the
temperature of the manure in the bed. In roomy or airy structures or
where only a small bed has been made it may, in the meantime, be left in
this condition. But in a tight cellar I find that the warm moisture
arising from the bed condenses in the atmosphere and settles on the top
of the manure, making it perfectly wet. In order to counteract this, as
soon as the bed is made up I spread some straw or hay over it loosely;
the moisture settles on the covering and does not reach through to the
manure. Beware of overcovering, as such induces overheating inside the
bed. At spawning time remove this covering. The bed will then have
become so cool (80° or 90°) that there is very little evaporation from
it, consequently little danger of surface-wetting.
=The Proper Temperature.=--This, in mushroom beds, depends upon the
materials of which they are composed, their thickness, how they are
built, the situation they are in, and other circumstances. If the manure
was good and fresh to begin with, carefully prepared and used as soon as
ready, the bed in a few days will warm up to 125°, or a little more or
less, and this is very good. My best beds have always shown a maximum
heat of between 120° and 125°. Had the manure been used a few days too
soon the heat would rise higher, perhaps to 135°, but this is too warm;
in this case I would fork over the surface of the bed a few inches deep
to let the heat escape, and after a couple of days compact the bed
again. Boring holes all over the surface of the beds with a crowbar is
the common way of reducing a too high temperature, and when the heat has
subsided sufficiently fill up these holes with finely pulverized dry
loam. With loam we can fill them up perfectly, but we can not do this
with manure, and if left open they remain as wet sweat holes that are
very deleterious to the spreading spawn.
A too high temperature in the beds should be sedulously guarded against,
for it wastes the substance of the manure, dries up the interior of the
bed, and the mushroom crop must necessarily be starved and short.
Provided that the manure is fresh and good and has been well prepared,
if the beds, after being made up, do not indicate more than 100° or 110°
no alarm need be felt, for excellent crops will likely be produced by
these beds. The thicker the beds are the higher the heat will probably
rise in them. Firmly built beds warm up more slowly than do loosely
built ones, and they keep their heat longer. If the materials are quite
cool when built solidly into beds they are not apt to become very warm
afterward. But I always like to make up the beds with moderately warm
manure.
It sometimes happens that circumstances may prevent the making up of the
beds just as soon as the manure is in prime condition, and even after
they are made up the heat does not rise above 75° or 80°. In such a case
if the manure is otherwise in good condition and fresh, it is well
enough and a good crop may be expected. But if the manure, to begin
with, had been a little stale, rotten and inert, I certainly would not
hesitate to at once break up the bed, add some fresh horse droppings to
it, mix thoroughly, then make it up again. Or a fair heat may be started
in such a stale bed by sprinkling it over rather freely with urine from
the barnyard, then forking the surface over two or three inches deep and
afterward compacting it slightly with the back of the fork. Spread a
layer of hay, straw, or strawy stable litter a few inches deep over the
bed till the heat rises. If the manure had been moist enough this
sprinkling should not be resorted to, but the fresh droppings added
instead. When it is applied, however, great care should be taken to
prevent overheating; a lessening or entire removal of the strawy
covering, and again firmly compacting the surface of the bed will reduce
the temperature. Some saltpeter, or nitrate of soda, an ounce to three
gallons of liquid, will encourage the spread of the mycelium after the
spawn is inserted; a much stronger solution of these salts can now be
used than would be safe to apply after the mycelium is running in the
bed.
When loam and manure mixed together comprise the materials of which the
bed is made, the temperature is not likely to rise so high as when
manure alone is used, but this matters not so long as the materials of
which the bed is composed are sweet and fresh and not over-moist. But if
the materials are cold and stale treat as recommended for a manure bed,
always bearing in mind that it is better to have a cold bed that is
fairly dry than one that is wet, or, indeed, a warm one that is wet.
Mr. Withington, of South Amboy, has a good word to say for beds of a low
temperature. He writes me: "Our beds kept in good bearing two months,
though they have borne in a desultory way a month longer. Our best bed
this season was one that was kept at an even temperature. The manure
never rose above 75° when made up, and decreased to about 60° soon after
spawning. Kept the house at 55°."