This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
We will consider a suitable sized bed is four feet wide by ten feet long, which will reqnire about one barrowful of material to each two feet in length. Collect for this enough horse droppings, fresh from the stable; place in a heap, in a dry and open- shed, protected from rain; let them become somewhat, but not too much heated by commencing fermentation; when so, torn them over daily, still retaining the warmth, and the lumps as whole as possible. In ten or twelve days, they will become nearly dry and mouldy looking; next, cover the flooring of the bed with two or three inches of stable straw-litter; upon this lay the prepared droppings, to the depth of ten to twelve inches, after being made solid; and remember, that the more compact, the better chance there will be of success. In the course of two or three days, it is probable that this bed, so made, will begin to heat; and if it should do so enough to burn the fingers if put into it, make a few holes with a stick, which will soon cool it down.
When there is surety that the warmth is on the decline, and has lowered to about 70° or 75°, break up some spawn into lumps of three inches cubic; plant one of each of these, at the distance of nine inches, just below the surface; afterwards, cover with two inches of turfy loam; beat and tread all down until quite hard and solid, and cover with any kind of soft hay or straw, excepting that from salt marshes. And here I would caution against allowing either salt or. lime from coming in contact with any portion of the material used for Mushrooms, as these ingredients will most assuredly kill the plant. The most suitable temperature is from 50° to 55°, with a corresponding moisture in solution in the atmosphere. Mushrooms will not develop in a dry heat, while too much wet and cold rots the spawn. I am thus particular in mentioning these details, because not only this but all other fungoids must have their own and peculiar requirements present, or they will not prosper. With these, there is nothing more easily grown than our present subject, and what is recorded above, if strictly adhered to, will undoubtedly lead to success. A bed thus made and cored for, will commence bearing in five or six weeks after being finished, and ought to continue to do so for two or three months.
If a regular succession be needed the year round, it will be necessary to make up a fresh bed once a month, and it only requires common intelligence, in addition to the above recorded ideas, to carry out the differences in the way of preparing the material according to the state of the weather. Sometimes it will be found that the young Mushrooms shrivel up while small, and consequently come to nothing more than clusters of small " buttons." This arises from one of two causes, viz: a deficiency of moisture, or by the covering lying too close, and thereby excluding the air. In the former case, the upper crust is dry, and crumbles between the fingers, when a sprinkling of clear water (enough to soak down about two inches) will remedy the evil; and, in the latter, if the surface be wet, the removal of and applying fresh covering, will answer the purpose.
Mushrooms can be also grown in pots or boxes filled with the above-mentioned materials, and in the same way. Pieces-of spawn may also be planted under the surface of the soil inside any grapery not at work in the fall, when the probability is, a crop with more or less certainty, until the base becomes too wet by the re-quieite supply of water for starting the vines. It is well known that Mushrooms are produced in great plenty, naturally, in some localities where cattle feed in the fall, after a dry summer; and if we consider these conditions, it will readily be seen how many suitable places there are around a homestead where the object in view may be carried put, when the nature of the plant is understood.
Without investigation, it might appear that this, and all other fungoids spring up primarily as spontaneous productions. Observation, however, shows this doctrine to be false, for, at the mature state of existence, they discharge an immense number of sporules, or cellular organs, from the parent body, which will develop and increase, in many instances, with wonderful rapidity, according to the species, when they come in contact with suitable food and atmospheric influences. It is a demonstrated fact, that the common Mushroom may be propagated in this way, and which any person may prove, by scattering the black powder that is emitted from an overgrown head on the surface of some of the compost which the spawn is made of; but as this method is not practicable in a general way, it is better to obtain the required substance as above directed.