Many who have a taste for horticultural pursuits grow mushrooms as much for the novelty of the thing as for the use, for it is certainly very gratifying for an amateur to find that he has succeeded with a crop of this curious vegetable in mid-winter, when everything outside is frost-locked and snow-bound. I have said that the novelty is attractive, for in growing all other plants the cultivator sees something tangible to start with, either seeds, plants, or roots, but with the mushroom it may be said he sees neither, for no seeds can be discovered either with the naked eye or with a magnifier, and it requires some faith to believe the minute thread-like substance we call "spawn," to be either plants or roots.
Mushrooms are always raised in the dark, and any cellar, stable, or an out-house of any sort, wherein a temperature of 45° to 65° can be commanded, will grow them. There are various methods followed by mushroom growers, but I will only give one, premising that if the directions given are strictly followed, success is just as certain as in growing a crop of peas or potatoes. Let horse droppings be procured from the stables each day, in quantities not less than a barrow load; to every barrow load of droppings, add half the quantity of fresh loam, from a pasture or sod land, or soil of any kind that has not been manured, (the objection to old manured soil being that it may contain the spores of spurious fungi.) Let the droppings and soil be mixed together day by day, as the manure can be procured; or if they can be had all at once in sufficient quantity, so much the better. Let the heap, (which should be under cover), be turned every day, so that it is not allowed to heat violently until you have got together a sufficient quantity to form a bed of the desired size. From the prepared droppings and soil, begin to form the bed. A convenient width is four feet, and the length may be as great as desired. First spread a thin layer of the compost, pounding it down firmly with a brick or mallet, layer after layer, until it reaches a depth of eight inches. Be careful that the thickness is just about eight inches, as if more, it would heat too violently, and if less, it would not heat enough. Into this bed plunge a thermometer; in two or three days the bed will heat, so that the thermometer will rise to 100° or over. As soon as the temperature declines to 90°, take a sharp stick and make holes an inch or so in diameter all over the bed, at about a foot apart, and six inches deep; into these holes drop two or three pieces of "spawn," and cover up the hole again with the compost of which the bed is made, and beat it slightly again, so that the bed will present the same level surface as before the spawn was put in. Let the bed remain in this condition for ten or twelve days, by which time the spawn will have run all through it. Now spread evenly over the surface of the bed about two inches of fresh loam, press it down moderately with the back of a spade, and cover up the bed with hay or straw to the thickness of three or four inches. If this operation is finished in November or December, and the place has an average temperature of 55°, you may look out for a crop in January or February. The bed will continue bearing about three or four weeks, and the crop is usually enormous, often producing a bushel on two square yards of space. After the first crop is gathered, a second, and even a third, can be taken if desired, from the same bed without further trouble than to spread a little fresh soil on the surface, giving it a gentle watering and covering up with hay as before. Great care must be taken that after placing the spawn in the newly made bed, the earth covering is not put on sooner than ten or twelve days; in my first attempt at mushroom growing, I failed two years in succession, because I put on the soil when the spawn was first put into the bed; by so doing, the steam arising from the manure was prevented from passing off, and the result was, that the spawn rotted. I believe this very common error is the cause of most of the failures in raising mushrooms.