Volume 10 Part 2 Article 17: Synthetic Casing for Mushroom Beds

Volume 10 Part 2 Article 17
Year 1979
Title: Synthetic Casing for Mushroom Beds
Author: B.B. Stoller


In mushroom growing it has been the practise since the sixteenth century in France to «case» the beds by placing a layer of material over the mushroom bed after the spawn has permeated the compost. This casing layer is usually one to two inches thick, and originally was loam soil. In 1947 I discovered that Peat could be substituted for this loam soil. I described my experiments and commercial practice with peat casing in my articles, “Studies on the Function of the Casing for Mushroom Beds”, Part I, Part II and Part III in the October, 1952, November, 1952 and December, 1952 Issues of the Mushroom Growers’ Association Bulletin, published in London, England. Other materials such as vermiculite, gravel, crushed brick and ashes have also been proposed.

The purpose or function of the casing material is to provide a medium which is insufficient in nutrients so that the mycelium growing into the casing is unable to form an abundance of the polyphenol oxidase enzymes, namely, Laccases, which produce the quinones that prevent fruiting. (Thequinonesare useful to the mushroom as a defensive mechanism, but must be destroyed in order to induce fruiting). The alkalinity, reducing substances, and possibly the reducing action by bacteria, occuring in the casing, also serve to destroy these quinone inhibitors volatilizing into the casing. The casing also serves as an additional source of moisture.

At the present time peat is widely used for casing mushroom beds but peat reserves suitable for casing mushroom beds are now being depleted. Also, the cost of baling and transporting peat is becoming expensive so that it would be highly desirable to provide a relatively inexpensive substitute for the peat.

Although various synthetic casings for mushroom beds have been proposed, none have produced the large yields to compete with peat or have been too expensive to have any practical application. In the formulas for a synthetic casing to be presented, I have discovered how to make a practical formula for commercial practice and a formula which will produce yields even higher than those obtainable with peat.

In accordance with my patent, U.S. #4,079,543, March 21, 1978, an inexpensive material that is highly absorptive to water is combined with activated carbon to absorb, remove or destroy emanations derived from mycelium that prevent fructification.
In addition, a casing material is provided which in some embodiments produces a much higher yield of mushrooms that can be obtained with conventional casing materials, such as peat.

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