MAKING UP THE MUSHROOM BEDS.

The place in the cellar, shed, house, or elsewhere, where we intend to grow the mushrooms, should be in readiness as soon as the manure has been well prepared and is in proper condition for use. The bed or beds should be made up at once. The thickness of the beds depends a good deal upon circumstances, such as the quality of the manure,—whether it is plain horse manure, or manure and loam mixed together,—or whether the beds are to be made in heated or unheated buildings, and on the floor or on shelves. Floor beds are generally nine to fifteen inches deep; about nine inches in the case of manure alone, in warm quarters, and ten to fourteen inches when manure and loam are used. In cool houses the beds are made a few inches deeper than this so as to keep up a steady, mild warmth for a long time. The beds may be made flat, or ridged, or like a rounded bank against the wall; but the flat form is the commonest, and the most convenient where shelves are also used in the same building. Shelf beds are generally nine inches deep; that is, the depth of one board.

In making up the beds, bring in the manure and shake it up loosely and spread it evenly over the bed, beating it down firmly with the back of the fork as you go along, and continue in this way until the desired depth is attained. If it is a floor bed and there is no impediment, as a shelf overhead, tread the manure down firmly and evenly; if the manure is fairly dry and in good condition it will be pretty firm and still springy, but if it is too moist and poorly prepared treading will pack it together like wet rotten dung.

Now pierce a hole in the bed and insert a thermometer. There are "ground" or "bottom-heat" thermometers, as gardeners call them, for this purpose, but any common thermometer will do well enough; and after two or three days examine this thermometer daily to see what is the temperature of the manure in the bed. In roomy or airy structures or where only a small bed has been made it may, in the meantime, be left in this condition. But in a tight cellar I find that the warm moisture arising from the bed condenses in the atmosphere and settles on the top of the manure, making it perfectly wet. In order to counteract this, as soon as the bed is made up I spread some straw or hay over it loosely; the moisture settles on the covering and does not reach through to the manure. Beware of overcovering, as such induces overheating inside the bed. At spawning time remove this covering. The bed will then have become so cool (80° or 90°) that there is very little evaporation from it, consequently little danger of surface-wetting.

The Proper Temperature.—This, in mushroom beds, depends upon the materials of which they are composed, their thickness, how they are built, the situation they are in, and other circumstances. If the manure was good and fresh to begin with, carefully prepared and used as soon as ready, the bed in a few days will warm up to 125°, or a little more or less, and this is very good. My best beds have always shown a maximum heat of between 120° and 125°. Had the manure been used a few days too soon the heat would rise higher, perhaps to 135°, but this is too warm; in this case I would fork over the surface of the bed a few inches deep to let the heat escape, and after a couple of days compact the bed again. Boring holes all over the surface of the beds with a crowbar is the common way of reducing a too high temperature, and when the heat has subsided sufficiently fill up these holes with finely pulverized dry loam. With loam we can fill them up perfectly, but we can not do this with manure, and if left open they remain as wet sweat holes that are very deleterious to the spreading spawn.

A too high temperature in the beds should be sedulously guarded against, for it wastes the substance of the manure, dries up the interior of the bed, and the mushroom crop must necessarily be starved and short.

Provided that the manure is fresh and good and has been well prepared, if the beds, after being made up, do not indicate more than 100° or 110° no alarm need be felt, for excellent crops will likely be produced by these beds. The thicker the beds are the higher the heat will probably rise in them. Firmly built beds warm up more slowly than do loosely built ones, and they keep their heat longer. If the materials are quite cool when built solidly into beds they are not apt to become very warm afterward. But I always like to make up the beds with moderately warm manure.

It sometimes happens that circumstances may prevent the making up of the beds just as soon as the manure is in prime condition, and even after they are made up the heat does not rise above 75° or 80°. In such a case if the manure is otherwise in good condition and fresh, it is well enough and a good crop may be expected. But if the manure, to begin with, had been a little stale, rotten and inert, I certainly would not hesitate to at once break up the bed, add some fresh horse droppings to it, mix thoroughly, then make it up again. Or a fair heat may be started in such a stale bed by sprinkling it over rather freely with urine from the barnyard, then forking the surface over two or three inches deep and afterward compacting it slightly with the back of the fork. Spread a layer of hay, straw, or strawy stable litter a few inches deep over the bed till the heat rises. If the manure had been moist enough this sprinkling should not be resorted to, but the fresh droppings added instead. When it is applied, however, great care should be taken to prevent overheating; a lessening or entire removal of the strawy covering, and again firmly compacting the surface of the bed will reduce the temperature. Some saltpeter, or nitrate of soda, an ounce to three gallons of liquid, will encourage the spread of the mycelium after the spawn is inserted; a much stronger solution of these salts can now be used than would be safe to apply after the mycelium is running in the bed.

When loam and manure mixed together comprise the materials of which the bed is made, the temperature is not likely to rise so high as when manure alone is used, but this matters not so long as the materials of which the bed is composed are sweet and fresh and not over-moist. But if the materials are cold and stale treat as recommended for a manure bed, always bearing in mind that it is better to have a cold bed that is fairly dry than one that is wet, or, indeed, a warm one that is wet.

Mr. Withington, of South Amboy, has a good word to say for beds of a low temperature. He writes me: "Our beds kept in good bearing two months, though they have borne in a desultory way a month longer. Our best bed this season was one that was kept at an even temperature. The manure never rose above 75° when made up, and decreased to about 60° soon after spawning. Kept the house at 55°."