“The manure is either used alone or with the mixture of some rich loamy soil, about one part of soil to four or five parts of manure. Most commercial growers of mushrooms do not employ any soil, but use the manure pure. This gives much less trouble and is usually considered a more successful method than the mixture of soil. When the beds are made up without soil, a layer of manure is spread over the bottom; usually the coarser and more strawy material is selected for the bottom layer since this ferments for a longer time and keeps up the heat in the bed. When the first layer of manure is thoroughly tramped or pounded down, another layer is added which in like manner is thoroughly tramped down. This is continued until the bed is filled, when the manure should be from 10-12 or 14 inches deep and must be firmly packed. In using soil to mix with the manure a layer of the manure is first put in the bottom of the bed as described. Over this is sprinkled a thin layer of soil. Another layer of manure is then added and another sprinkling of soil. Each time the layers are thoroughly packed down, as before, until the beds are filled.”
