The following paragraphs are from “Farmers’ Bulletin,” No. 53 (by William Falconer), of the U.S. Dept. of Agriculture (March, 1897):—
Mushrooms are a winter crop, coming in from September till April or May—that is, the work of preparing the manure begins in September and ends in February, and the packing of the crop begins in October or November and ends in May. Under extraordinary conditions the season may begin earlier and last longer, and, in fact, it may continue all summer.
Mushrooms can be grown almost anywhere out of doors, and also indoors where there is a dry bottom in which to set the beds, where a uniform and moderate temperature can be maintained, and where the beds can be protected from wet overhead, and from winds, drought, and direct sunshine. Among the most desirable places in which to grow mushrooms are barns, cellars, closed tunnels, sheds, pits, greenhouses, and regular mushroom houses. Total darkness is not imperative, for mushrooms grow well in open light if shaded from sunshine. The temperature and moisture are more apt to be equable in dark places than in open, light ones, and it is largely for this reason that mushroom houses are kept dark.
The best fertilizer for mushrooms, so far as the writer’s experience goes, is fresh horse manure. Get together a lot of this material (short and strawy) that has been well trampled and wetted in the stable. Throw it into a heap, wet it well if it is at all dry, and let it heat. When it begins to steam, turn it over, shake it well so as to mix thoroughly and evenly, and then tramp it down solid. After this let it stand till it again gets quite warm; then turn, shake, trample as before, and add water freely if it is getting dry. Repeat this turning, moistening, and trampling as often as it is needful to keep the manure from “burning.” If it gets intensely hot, spread it out to cool, after which again throw it together. After being turned in this way several times, and the heat in it is not apt to rise above 130° F., it should be ready to make up in the beds. By adding to the manure at the second or third turning one-fourth or one-fifth of its bulk of loam, the tendency to intense heating is lessened and its usefulness not at all impaired. Some growers prefer short manure exclusively, that is, the horse droppings, while others like a good deal of straw mixed in with this. The writer’s experience, however, is that, if properly prepared, it matters little which is used.
Ordinarily the beds are only 8 to 10 inches deep; that is, they are faced with 10-inch-wide hemlock boards, and are only the depth of this board. In such beds put a layer of fresh, moist, hot manure, and trample it down firm until it constitutes half the depth of the bed; then fill up with the prepared manure, which should be rather cool (100° to 115°F.) when used, and pack all firmly. If desired, the beds can be made up entirely of the prepared manure. Shelf beds are usually 9 inches deep; that is, the shelf is bottomed with 1-inch boards and faced with 10-inch wide boards. This allows about 8 inches for manure, and 1 inch rising to 2 inches of loam on top. In filling the shelf beds the bottom half may be of fresh, moist or wettish, hot manure, packed down solid, and the top half of rather cool prepared manure, or it may be made up of all prepared manure. As the shelf beds cannot be trodden and cannot be beaten very firm with the back of the fork, a brick is used in addition to the fork.
The beds should be spawned after the heat in them has fallen below 100° F. The writer considers 90° F. about the best temperature for spawning. If the beds have been covered with hay, straw, litter, or mats, these should be removed. Break each brick into twelve or fifteen pieces. The rows should be, say, 1 foot apart, the first one being 6 inches from the edge, and the pieces should be 9 inches apart in the row. Commencing with the first row, lift up each piece, raise 2 to 3 inches of the manure with the hand, and into this hole place the piece, covering over tightly with the manure. When the entire bed is spawned, pack the surface all over. It is well to cover the beds again with straw, hay, or mats, to keep the surface equally moist. The flake spawn is planted in the same way as the brick spawn, only not quite so deep.
At the end of eight or nine days the mulching should be removed and the beds covered with a layer of good loam 2 inches thick, so that the mushrooms can come up in and through it. This gives them a firm hold, and to a large extent improves their quality and texture. Any fair loam will do. That from an ordinary field, wayside, or garden is generally used, and it answers admirably. There exists an idea that garden soil surfeited with old manure is unfit for mushroom beds because it is apt to produce spurious fungi. This, however, is not the case. In fact, it is the earth most commonly used. For molding the beds the loam should be rather fine, free, and mellow, so that it can be easily and evenly spread and compacted firmly into the manure.
If an even atmospheric temperature of from 55° to 60° F. can be maintained, and the house or cellar containing the mushroom beds is kept close and free from drafts, the beds may be left uncovered, and should be watered if they become dry. But no matter where the beds are situated, it is well to lay some loose hay or straw or some old matting or carpet over them to keep them moist. The covering, however, should be removed just as soon as the young mushrooms begin to appear above ground. If the atmosphere is dry, the pathways and walls should be sprinkled with water. The mulching should also be sprinkled, but not enough to cause the water to soak into the bed. However, if the bed should get dry, do not hesitate to water it.
Mustard.—Almost all the mustards are good for greens, though white mustard is usually best. Chinese mustard is also valuable.
Seed should be sown in drills, 3 to 3-1/2 feet apart, and covered with a half inch of soil. The ease with which they may be grown, and the abundance of herbage which they yield, mark their special utility. Sow very early for spring greens, and in late summer or early September for fall greens.