If there is any likelihood of the surface manure getting wet from the condensed moisture of the atmosphere, I would again cover over the beds with some hay or straw, and let it remain on until molding time. And if the bed is a little sluggish,—that is, cool,—this covering will help in keeping it warm. Outside beds should be molded over in three or four days after spawning; inside beds in eight to ten days.
Steeped Spawn.—As brick spawn is so hard and dry I have tried the effect of steeping it in tepid water before planting; some pieces were merely dipped in the water, and others allowed to soak in the pails one-half, one, five, and ten hours. The effect was prejudicial in every instance and ruinous in the case of the long-soaked pieces.
Flake Spawn.—"This is produced by breaking up the brick spawn into pieces about two inches square and mixing them in a heap of manure that is fermenting gently. After lying in this heap about three weeks it will be found one mass of spawn, and just in the right condition for running vigorously all through the bed in a very short time.... When flake spawn is used the appearance of the crop is from two to three weeks earlier than when brick spawn is used."—Mr. Henshaw, in first edition of "Henderson's Handbook of Plants." I have tried this method and given it careful attention, but the results were inferior to those obtained where plain, common brick spawn had been used at once.
In all my practice I have found that any disturbance of the spawn when in active growth which would cause a breaking, exposing, or arresting of the threads of the mycelium has always had a weakening influence upon it. I have transplanted pieces of working spawn from one bed to another, as the French growers do, but am satisfied that I get better crops and larger mushrooms from beds spawned with dry spawn than from beds planted with working spawn from any other beds.
CHAPTER XII.
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.