Home Mushroom Cultivation with Hydrogen Peroxide
Volume I
R. Rush Wayne, Ph.D.
Introduction
When I first took an interest in growing mushrooms, I checked out a well-known book on mushroom cultivation from the library and eagerly read through it. But my interest soon turned to general discouragement as I read about all the equipment and procedures the book insisted were necessary to grow mushrooms without getting the cultures contaminated. I would need a sterile laboratory space with a laminar-flow hood fitted with electrostatic and HEPA filters and an ultraviolet light.
This space would need a sterile air-lock entry way with a foot wash, and I would need to
have special clothing to enter it, so that I could wash down the floors with chlorine bleach
every day. My fruiting mushrooms would have to be grown in a separate building together, so as to avoid getting spores into the sterile laboratory. These fruiting cultures would have to be grown in specially designed plastic bags with microporous filter patches attached, so that the mushroom mycelium could get oxygen without letting mold spores or bacteria get in. Of course, I would need an autoclave or at least a specially designed pressure cooker to sterilize the media that went into these bags.
After considering these requirements briefly, I put aside the thought of growing mushrooms. I wasn’t about to get all that equipment, and I figured I probably wasn’t cut out for the job anyway. From what I could gather, my house would be a
death trap for mushroom cultures. Neither my wife nor I are careful housekeepers. We have unabashed dust and clutter, and green and white fuzzy things can be found in and outside the refrigerator. Although I was skilled at sterile technique from my years as a graduate student in biochemistry, I didn’t think that would save me from the legions of eager contaminants that would surely dog my every movement should I attempt to grow anything so delectable as mushrooms.
Still, the thought of growing mushrooms didn’t disappear entirely. Instead, a year or so later, it resurfaced again in the form of a new idea. I had read that culture media used for growing orchid seeds could be rendered free of contaminants if hydrogen peroxide was added to the medium. While the peroxide killed bacteria, yeast, and fungal spores, it left the orchid seeds viable because they contained enough peroxide-decomposing enzymes to protect themselves. Then the orchid seeds could be germinated and tended easily by relative beginners without the need for strict sterile technique.
So here was a question: could added peroxide be used to keep mushroom-growing media, like orchid seed media, free of contaminants? If it could, then perhaps mushroom growing could be made accessible to beginners, just like orchid seed germination. So I resolved to try it with mushroom mycelium.
What followed was a fairly complicated and non-linear process of learning about growing various mushrooms, experimenting with adding hydrogen peroxide, trying different concentrations, learning about different culture media and how they interacted with the mushrooms and the peroxide, trying various degrees and techniques of pasteurization and sterilization, going back over earlier ground with better pH measurements, experimenting with supplements, tracking down sources of contamination, tightening my procedures, and on and on, until I developed some fairly reliable guidelines for what I was doing. It all took far longer than I ever would have guessed. But the upshot of it was that, yes, mushroom growing can be made accessible to beginners without the need for sterile facilities, air filtration, or even a pressure cooker, if one adds hydrogen peroxide to help keep the mushroom culture media free of contaminants. Using the techniques I developed, all the stages of mushroom culture can now be carried out by relative beginners, with a wide variety of mushrooms, and without investing a small fortune in equipment and facilities.
I have written the current book as a guide for the home hobbyist interested in mushroom growing, one that could serve as a basic stand-alone primer on home cultivation of several delectable mushroom species, and one that anyone can use, including the beginner. My previous manual,
Growing Mushrooms with Hydrogen Peroxide, was written for the mushroom grower who is already familiar with traditional methods of mushroom cultivation, and its focus is on the use of hydrogen peroxide as an improvement to the traditional methods. While that manual made it
possible for the first time to perform all phases of gourmet mushroom cultivation in the home without sterile facilities and air filtration, the current book goes even further and presents procedures that do not require pressure sterilization.
Of course, not all of the procedures described in this book were created by me. In particular, any procedures not specifically required for using the peroxide technique, or not specifically made possible by the peroxide technique, are likely to have originated elsewhere.
For in depth accounts of the traditional methods of mushroom cultivation, as well as the growth requirements for a wide range of mushroom species, please consult Stamets, Growing Gourmet and Medicinal Mushrooms, Chilton and Stamets, The Mushroom Cultivator, or another basic text. These books are valuable reference volumes for anyone who seriously wants to pursue mushroom growing in detail. Also, as you glance through these books, with page after page of discussion of elaborate sterile procedures and sources of contamination, you will enhance your appreciation for the simple techniques contained in this manual.
Note that sterile or aseptic technique, which the procedures in this book require to some extent, is always better demonstrated than described. It is my hope that the reader will seek out direct instruction in this regard. Your local mycological society may be helpful to that end. Also note that this book is not intended as a guide for commercial cultivation of mushrooms, although the methods described here may well prove valuable to small scale commercial growers as well as to home hobbyists.
Preliminaries
The Mushrooms
Just about any mushroom that is currently cultivated can be grown in the home. However, some are easier to grow than others, and some, though easy, are not as rewarding as others that are more difficult.
I currently focus on four mushrooms in my own home growing. These are:
Hypsizygus ulmarius, the elm oyster or white elm mushroom: although it is not a member of the oyster mushroom family, it is an oyster-style mushroom in appearance and habit. It grows aggressively on sawdust or straw, it rarely has contamination problems following the techniques described here, and it does well in a variety of conditions and temperatures, fruiting either vertically or horizontally. When well cultivated, the mushrooms are large and attractive, rather like strange white flowers, and they are in my opinion the most delicious of the oyster-style mushrooms (not counting P. eryngii).
Pleurotus eryngii or King oyster: a member of the oyster mushroom family, but it does not have the usual oyster mushroom appearance or habit. A native of Europe, it grows up from the ground in a regal stance, rather than on trees and logs. It is large and thick-fleshed. Its substrate requirements are more narrow than other oysters, as are its temperature requirements. I have read that it prefers sawdust to straw, although I have not experimented enough with it on straw to confirm or deny this. It fruits best in fall or spring temperatures, growing at a glacial pace in the cold of winter, and dying back in the hotter parts of the summer. It is one of the most delicious of cultivated mushrooms if cooked properly, sauteed rapidly in a wide pan, without being allowed to stew in its own juice, then lightly salted.
Hericium erinaceus or Lion’s Mane, also called Pom Pom mushroom: a fungus that lacks the stalk and cap of a traditional grocery store mushroom, instead appearing as a kind of snowball covered with white icicles. It grows rapidly on sawdust substrates, and fruits easily over a range of temperatures. I have heard that it can be grown on straw as well, although I have never tried it.
Chefs love this mushroom, and indeed it has a delicious gourmet flavor sometimes tasting like lobster.
Agaricus subrufescens, or almond mushroom: a member of the family that includes the domestic button mushroom and the Portabellas. It is distinguished by its unmistakable flavor of almond extract. Like the domestic mushroom, it prefers to grow on compost, but it can also be grown on straw, wood chips, or supplemented sawdust. It is a warm weather mushroom, but it will also fruit indoors in the winter in a heated room, making it a good candidate for year-round cultivation.
This mushroom generally needs a casing layer--a layer of friable, soil-like mixture usually
containing peat--applied to the surface of the culture in order to form fruiting bodies.
Some other mushrooms to consider include:
Lentinula edodes or Shiitake: ever popular, grown by many people and written about extensively elsewhere. I am not a shiitake grower, but the methods of culture handling, spawn and substrate preparation described here will all work for shiitake as well as for the mushrooms that I normally grow. Be sure to get a shiitake strain selected for growth on sawdust if you decide to grow this species using pellet fuel as your bulk substrate. Warm weather and cool weather strains are available.
Pleurotus ostreatus and other oyster mushroom species: like H. ulmarius, these are among the easiest mushrooms to grow, racing through sawdust or straw or any of a variety of other substrates. They were the first mushrooms I fruited using the peroxide method. Strains exist for most temperature ranges. The spores of P. ostreatus, which are released in great quantity from mature fruiting bodies, can cause health problems.
Ganoderma lucidum or Reishi: a top flight medicinal mushroom with immune stimulating properties. This mushroom grows on hardwood sawdust in warm temperatures. A related species from the Pacific Northwest, Ganoderma oregonense, prefers cooler temperatures. The woody mushrooms are broken up and made into tea.
Coprinus comatus or Shaggy Mane: a mild tasting, short-lived mushroom that grows best on compost.
I never got it to fruit indoors, but after I discarded the cultures in my yard, it appeared in my garden for a couple of seasons.
Hypsizygus tessulatus, or Shimeji: a cute, small round mushroom with a crunchy texture, grows on straw or sawdust-based substrates. The strain I bought required near freezing temperatures to initiate fruiting, so I didn’t experiment much with it, but there are presumably others that will fruit without that.
Stropharia rugosa-annulata, or King Stropharia: a large mushroom that grows on beds of wood chips or straw and requires a casing and warm weather to fruit. The mycelium grows slowly, and only one variety is currently known to fruit indoors without regards to season of the year.
Agaricus bisporus/Agaricus brunnescens, or the white button mushroom, also the brown button mushroom, crimini and portobellos: so many button mushrooms are now grown by large commercial farms in the US, and sold so cheaply, that these companies can no longer make a profit. Like the almond mushroom, the preferred growth substrate for button mushrooms and portobellos is compost. Preparation of quality compost is a complicated and labor-intensive process that is beyond the scope of this manual. But button mushrooms can also be grown on straw prepared by the peroxide
method (see Volume II). The yield will not be as high as on compost, but straw is so much easier to prepare at home that you probably won't miss the extra yield. As with the almond mushroom, a casing layer is required for fruiting, but button mushrooms require cooler conditions. Spawn can be prepared with pressure cooked grain (this volume) or with steamed instant rice (see Volume II, "Ten Minute Grain Spawn").
