LOAM FOR THE BEDS.
In growing mushrooms we need loam for casing the beds after they are
spawned, topdressing the bearing beds when they first show signs of
exhaustion, filling up the cavities in the surface of the beds caused by
the removal of the mushroom stumps, and for mixing with manure to form
the beds. The selection of soil depends a good deal on what kind of soil
we have at hand, or can readily obtain.
The best kind of loam for every purpose in connection with
mushroom-growing is rich, fresh, mellow soil, such as florists eagerly
seek for potting and other greenhouse purposes. In early fall I get
together a pile of fresh sod loam, that is, the top spit from a pasture
field, but do not add any manure to it. Of course, while this contains a
good deal of grassy sod there is much fine soil among it, and this is
what I use for mushrooms. Before using it I break up the sods with a
spade or fork, throw aside the very toughest parts of them, and use the
finer earthy portion, but always in its rough state, and never sifted.
The green, soddy parts that are not too rough are allowed to remain in
the soil, for they do no harm whatever, either in arresting the mycelium
or checking the mushrooms, and there is no danger that the grass would
grow up and smother the mushrooms.
Common loam from an open, well-drained fallow field is good, and, if the
soil is naturally rich, excellent for any purpose. But do not take it
from the wet parts of the fields. Reject all stones, rough clods,
tussocks, and the like. Such loam may be used at once.
Ordinary garden soil is used more frequently than any other sort, and
altogether with highly satisfactory results. The greatest objection I
have to it is the amount of insects it is apt to contain on account of
its often repeated heavy manurings.
Roadside dirt, whether loamy or gritty, may also be used with good
results. If free from weeds, sticks, stones and rough drift, it may be
used at once, but it is much better to stack it in a pile to rot for a
few months before using.
Sandy soil, such as occurs in the water-shed drifts along the roads and
where it has been washed into the fields, is much inferior to stiffer
and more fibrous earth.
I have used the rich dark colored soil from slopes and dry hollows in
woods, and, odd though it may appear, as mushrooms do not naturally grow
in woods, with success. But it is not as good as loam from the open
field.
Peat soil or swamp muck that has been composted for two or three years
has failed to give me good returns. The mushrooms will come up through
it all right, but they do not take kindly to it.
Heavy, clayey loam is, in one way, excellent, in another, not so good.
So long as we can keep it equably moist without making it muddy it is
all right, but if we let it get a little too dry it cracks, and in this
way breaks the threads of the spawn and ruins the mushrooms that were
fed through them.
=Loam Containing Old Manure.=--Loam in which there is a good deal of
old, undecomposed manure, such as the rich soil of our vegetable
gardens, is unqualifiedly condemned by some writers because of the
quantity of spurious and noxious fungi it is supposed to produce when
used in mushroom beds. But I can not join in this denunciation because
my experience does not justify it. This earth is the only kind used by
many market gardeners, as they have no other, and certainly without
apparent injurious effect. When I was connected with the London market
gardens, some twenty years ago, Steele, Bagley, Broadbent, and the other
large mushroom growers in the Fulham Fields cased all of their beds with
the common garden soil--perhaps the most manure-filled soil on the face
of the earth--and spurious fungi never troubled them. Indeed, I can not
understand why it should produce baneful crops of toadstools when used
in mushroom beds, and no toadstools when used for other horticultural
purposes, as on our carnation benches in greenhouses, in our lettuce or
cucumber beds, or in the case of potted plants. True, spurious fungi may
appear in the earth on our greenhouse benches or frame beds or mushroom
beds at any time and in more or less quantity, but I am convinced that
the rich earth of the vegetable garden has no more to do with producing
toadstools than has any other good soil, and old manure has far less to
do with it than has fresh manure.
All practical gardeners know how apt hotbeds, in spring when their heat
is on the decline, are to produce a number of toadstools; and, also,
that when the bed is "spent," that is, when the heat is altogether gone,
the tendency to bear toadstools has gone too. This peculiarity is more
apparent in spring than in fall. All mushroom growers know that spurious
fungi, when they appear at all, are most numerous three to two weeks
before it is time for the mushrooms to come in sight. The same growth
appears in the manure piles out in the yard; a few weeks after the
strong heat of the manure has gone lots of toadstools may be observed on
and about the heaps, but on the piles of well-rotted cold manure we
seldom find toadstools at all.
The fresh, clean stable manure used in mushroom-growing is not apt to be
charged with the spores of pernicious toadstools; their presence is
always most marked in the case of mixed manures.
And there is a current idea that mushrooms will not thrive in beds in
which old manure abounds, either in the loam or fermenting material;
that it kills the mycelium. This, too, I must refute. I have seen heavy
crops of spontaneous mushrooms come up in violet and carnation beds in
winter, and where the soil consisted of at least one-fourth of rotted
manure well mixed with the earth. In cucumber and lettuce beds the same
thing has taken place. And in similar beds that have been planted
artificially with spawn, good crops of mushrooms have also been raised,
and the mycelium, instead of evading the lumps of old manure in the soil
often forms a white web right through them.