Procure not less than a cartload of clean, fresh stable manure. Place it under cover, to protect it from rain and drain water, mix well and heap up the whole mass into a mound three feet high then beat the mound firmly down to prevent undue heating. Repeat this operation every other day until its rank smell is gone, taking care that on each turning the outside dry manure is placed in the centre of the mound. By this means the stable odor is dissipated while its heating properties are equally distributed. Add to this from one-fourth to one-fifth of clean, rich garden mould. Mix well. After this careful handling, the mass may be considered fit for bedding purposes. When placed in the beds the mass should be compacted again by beating with the back of a spade or trowel. The bed surface should appear moist but not wet, smooth and of firm consistence. From day to day it will be necessary to test its general temperature by means of a thermometer. To this end make at various places at different depths openings sufficiently large to admit the use of a thermometer. It will be found that the temperature is highest nearest the bottom. Test at various points. At first the temperature will run high; 105° to 120° Fahrenheit is probably as high as it will reach, but in a few days it will fall to 85° or 80° Fahrenheit. At this point spawn the bed. For this purpose make holes in the top of the bed about six inches apart and two inches deep with a blunt dibble or broom handle. Place in these holes or openings a piece of brick spawn about the size of a hen's egg, and cover the holes with manure; finish by packing the same, keeping the surface of the bed smooth and moist. The spawn should be slightly moistened before using. Should the surface of the bed become dry, use water from a fine sprinkling pan. The temperature of the cellar or house in which the bed may be placed should range between 55° and 75°, and should not be lower than 50°. If the spawn is good and all conditions attended to, the white filaments should appear spreading through the bed within eight or ten days after spawning. When the white spawn is observed on or near the surface, cover the whole surface with from one to two inches of garden loam well pulverized. A good general rule for spawning the bed is to wait until the heat of the bed is on the decline and has fallen to at least 90° Fahrenheit. If the heat in the middle of the bed runs too high the spawn is killed. The experience of a number of growers has shown that a bed spawned at 60° to 80° and kept at 55° after the mushrooms appear gives better results than one spawned at 90°.

The quality of the manure makes some difference in its temperature. That obtained from stables where horses are grass fed will be of lower normal temperature and will chill quicker than that obtained from corn or oat fed stock.

A solution of saltpeter in proportion of about fifteen grains to a quart of water, occasionally spread over the bed with a fine hose, helps to accelerate the growth of the mushrooms.

The proper condition of the manure as regards dryness or moistness can be readily ascertained by squeezing it in the hand; it should be unctuous enough to hold together in a lump, and so dry that you cannot squeeze a drop of water out of it. Excessive moisture in the manure has been often a cause of failure. It should be remembered also that when the heat of the manure is on the decline it falls rapidly, five, often ten degrees a day, till it reaches about 75°, and between that and 65° it may rest for weeks.

One of the principal causes of the failure of mushroom culture in this country is the use of old or poor spawn. Good spawn should have a fresh, mushroomy odor, and a bluish-white appearance on the surface. In buying spawn one should always go to reliable seedsmen.