For the market the mushrooms are sorted as to size and color, and packed in one, two or five-pound boxes or baskets. Since they are very perishable, they must reach the market in the shortest time.
OLD BEDS.—It is not practicable to raise another crop of mushrooms in the material of an old bed, although this material is still valuable for garden purposes. The old material should be entirely removed, and the mushroom house thoroughly cleaned before the new beds are made. If this precaution be omitted the next crop may suffer from the diseases or enemies of the mushrooms.
Figure 502.—A Cluster of 50 Mushrooms on One Root, Grown from "Lambert's Pure Culture Spawn" of the American Spawn Co., St. Paul, Minn.
SPAWN.—The cultivated mushroom is propagated from "spawn," the commercial name applied to the mycelium; the term "spawn" includes both the mycelium and the medium in which it is carried and preserved. Spawn may be procured in the market in two forms, flake spawn and brick spawn. In both forms the mycelium growth is started on a prepared medium mainly consisting of manure and then arrested and dried. The flake spawn is short-lived by reason of its loose form, in which the mycelium is easily accessible to the air and destructive bacteria. It deteriorates rapidly in transportation and storage and can only be used to advantage when fresh. Growers, especially in the United States, have therefore discarded it in favor of brick spawn, which affords more protection to the mycelium and can be safely transported and stored for a reasonable period.
Until recently the manufacturer of spawn was compelled to rely entirely upon the caprice of nature for his supply. The only method known consisted in gathering the wild spawn wherever nature had deposited it and running the same into bricks or in loose material, without reference to variety. Neither the manufacturer nor the grower had any means of ascertaining the probable nature of the crop until the mushrooms appeared.
Figure 503.—Agaricus villaticus.