Never use old manure or manure mixed with shavings or sawdust.
Place the fresh manure in a neat pile and cover with two or three inches of earth.
In the course of three or four days turn the manure over, shaking and mixing the earth in thoroughly. Add water if necessary to keep the manure in reasonably moist condition.
Cover again with earth which will be sufficient, and allow the pile to heat, through the action of bacteria in the manure, for five or six days. Then turn again, shaking up thoroughly each time, and turning the outer dried or whitened portion of the pile toward the centre. Add water with a sprinkler when necessary to keep plenty of moisture. After about four turnings in this way, covering a period of three or four weeks the manure will be sufficiently rotted and decomposed to make into the beds.
MAKING THE BEDS
The manure should be placed on the floor or prepared bed spaces to a depth of 8 to 10 inches in winter weather. In warm weather 6 or 7 inches are enough.
The compost should be compressed in making the bed and provided it is not too wet it may be tramped, which prevents too much drying out, while the manure is heating in the beds.
The only practical test of the proper moisture content of the manure at time of making beds, is when upon compression in the hand water cannot readily be squeezed out of it.
After the beds are made up they should be covered and allowed to heat for a week or ten days. After this length of time the temperature should be watched until it falls to 70 degrees, when the beds may safely be spawned. The temperature may be obtained by inserting a common glass thermometer in the manure.
During the process of heating, after the beds are made up, the temperature often rises as high as 125 degrees, and it is never safe to spawn until it falls to 70 degrees.