Earthing over the beds.
This is an important operation in
mushroom-growing, and the one for which loam is indispensable.
It consists in covering the manure beds, after they
have been spawned, with a coating, or casing as it
is more commonly called, of loam. The spawn spreads
in the manure and rises up into the casing, where
most of the young mushrooms develop, and all find
a firm foothold. The loam also contributes to
their sustenance. And it protects the manure,
hence the spawn, from sudden fluctuations of temperature,
and preserves it from undue wetting or drying.
The best soil to use for this purpose
is rich, fibrous, mellow loam, such as is described,
page 100.
If the manure is fresh and in good
condition and the beds are in a snug cellar or closed
mushroom house, I would not case them until the second
week after spawning, say about the eighth or tenth
day; but were these same beds in an open, airy shed
or other building I would case them over some days
earlier, say the fourth or fifth day. A fear is
often expressed that when beds are cased within three
or four days after being spawned the close exclusion
of the manure from the air is apt to raise the heat
of the manure in the bed, and thereby destroy the spawn;
but I have never known of any truth in this theory,
and with well-prepared manure I am satisfied no brisk
reheating takes place, at least the thermometer does
not indicate it. The great danger of early casing
is in killing the spawn by burying it too deep in
damp material and before it has begun to run through
the manure.
I have conducted several experiments
in order to satisfy myself regarding when is the proper
time to case the beds, and have found no difference
in results between beds that were cased over as soon
as they were spawned and others that were not cased
over until the fourth, seventh, tenth, or fourteenth
day after spawning. The good or bad results in
the time of casing depend on the condition of the manure
in the beds, the depth at which the spawn has been
inserted, the openness or closeness of the place in
which the beds are situated, and other cultural conditions.
But to delay casing as late as the fifteenth or sixteenth
day after spawning is injurious to the crop, because
in applying the covering of soil we are sure to break
many of the mycelium threads that have by this time
so freely permeated the surface of the manure.
After the fourth week little white knots may be observed
here and there on the spawn threads; these are forming
mushrooms, and to delay casing the bed until this
time would smother these little pinheads, and greatly
mar our prospects of a good crop.
Peter Henderson, in his invaluable
work, “Gardening for Profit,” has given
rise to a deep seated prejudice against molding over
mushroom beds as soon as they are spawned by telling
us that in his first attempt at mushroom-growing he
had labored for two years without being able to produce
a single mushroom, and all because he molded over his
beds with a two-inch casing of loam just as soon as
he had spawned them. Then he changed his tactics,
and did not mold over the beds until the tenth or
twelfth day after spawning, and was rewarded with good
crops of mushrooms. Now, notwithstanding Mr.
Henderson’s experience, it is a fact that many
excellent growers spawn and mold their beds the same
day, and with success. But Mr. H. has done much
good in displaying a rock against which many might
be wrecked, so much depends upon other cultural conditions.
The old practice of inserting the spawn three or more
inches deep into the manure bed and then molding it
at once with two inches deep of loam was enough to
destroy the most potent spawn; nowadays we barely
cover the spawn with the manure, and this is how molding
over at once is so successful.
All the preparation necessary is to
have the loam in medium dry, mellow condition, well
broken up with the spade or digging fork, and freed
from sticks, stones, big roots, clods, chunks of old
manure, and the like.
Sifting the soil for casing the beds
is labor lost. Sifted soil has no advantage over
unsifted earth, except when it is to be used for topdressing
the bearing beds or filling up the holes in their surface.
The condition of the soil should be
mellow but inclined to moist. If wet it can only
be used clumsily and spread with difficulty; if dry
it can be spread easily but not made firm, and on
ridge beds can not be put on evenly. But when
moderately moist it can be spread easily and evenly
on flat or rounded surfaces, and made firm and smooth.
How deep the mold shall be put upon
the bed is also an unsettled question. Some growers
recommend three-fourths of an inch, others one, one
and one-half, two, or two and one-half inches, and
some of our best growers of fifty or seventy-five
years ago were emphatic in asserting three inches
as the proper depth, but among recent writers I do
not find any who go beyond two and one-half inches.
My own experience is in favor of a heavy covering,
say one and one-half to two inches. In the case
of a thin covering the mushrooms come up all right
but their texture is not as solid as it is in the
case of a heavy covering, nor do the beds continue
as long in bearing; besides, “fogging off”
is much more prevalent under thinly covered than under
heavily covered beds; also, when the coating of loam
is heavy a great many more of the “pinheads”
develop into full sized mushrooms than in the case
of thinly molded beds.
Opinions differ as to firming the
soil. I am in favor of packing the soil quite
firm, and have never seen good mushrooms that could
not come through a well firmed casing of loam, and
I never knew of an instance where firm casing stopped
or checked the spreading of the mycelium or the development
of the mushrooms. In the case of flat beds, for
instance, those made on shelves and floors, a
slightly compacted coating (and this is all Mr. J.
G. Gardner uses) may be all right, but in the case
of alongside-of-walls, ridge, and other rounded beds
I much prefer and always use solidly compacted casings.
Mr. Henshaw has for several years
used green sods about two inches thick, put all over
the bed, grass side down, and beaten firmly. The
advantage of using sods instead of soil, he thinks,
is that the young clusters of mushrooms never damp
or “fogg off” as they are apt to do when
soil is used.
I have given this green sods method
repeated and careful trials, and am satisfied that
it has no advantages, in any way, over common fibrous
loam; indeed, it is not as good. No matter how
firmly a sod, having its green side down, may be beaten
on to a bed of manure, there is barely any union between
the two; the sod merely rests upon the dung, but so
closely that the mycelium enters it freely. A
slight movement or displacement of the sod after the
spawn enters it will break the threads of mycelium
between the manure and the sod, and this will destroy
the immature mushrooms forming in the sod. This
gave me a good deal of trouble. Stepping on the
sod would disturb it. A clump of strong mushrooms
formed under it sometimes displaces it in forcing their
way to the surface.
Sods are only fit for use on flat
beds where they can lie solid; on rounded or ridge
beds they are too liable to be disturbed. And
the trouble and expense of procuring sods are too
great to warrant their use, even if they had any advantages.