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“In thinking of ways in which soil life assists us to produce crops, it itself becomes a crop.” –Bill Mollison

As many gardeners are aware, fungi is extremely import for soil life since it cycles organic matter, makes nutrients available for plants, and helps give soil its crumbly structure (tilth) to bind those nutrients. Fungi is an integral part of our ecosystem that we live in and are apart of. While popular culture often focuses on negative interactions with fungi (mushroom poisoning, mold in dwellings, pathogens, etc.) many species of fungi are directly useful to us as food, medicine, dyes, fermentation and bioremediation.

The usefulness of fungi originally spurred me to learn more about it. I became amazed with how mycology, the study of fungi, often challenges common sense. For example, when one sees different species of trees in a forest one usually assumes these two trees are separate, competing organisms. Yet fungal mycorrhiza has been seen transporting nutrients between different species of trees in order to balance the overall health of the ecosystem.

Not only did I discover how intriguing fungi can be but also how the cultivation of beneficial fungi takes very little effort. Small scale cultivation of useful fungi can recycle wastes, increase on-site food/medicine yields, supplement income, and assist in soil-building with minimal inputs. Just like with growing plants, there are some basic fundamentals that we must recognize in order to create the conditions necessary for fungi to thrive. Through integrating ourselves with fungi we can also thrive.

Mycology 101

There are 1-2 million species of organisms in the kingdom of fungi, a separate kingdom from plants, animals and bacteria. In addition to mushrooms, mold and yeast are also fungi. Genetically, animals share more DNA with fungi than with plants or bacteria. Some classification schemes even include animals and fungi in the same kingdom. Yet only about 14,000 mushroom-forming fungal species have been identified—another 90% have yet to be discovered.

Have you ever seen the white thread-like roots on the bottom of decomposing wood, leaves or cardboard? This is mycelium, the “vegetative” form of fungus, digesting and breaking down organic matter, turning it back into soil.

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Mushroom with mycelium visible at the base. This is Clitocybe nuda or blewit, a choice edible common in the fall to most of the US. 

Since popular knowledge of plants often exceeds that of fungi, a simple analogy can help:

   Tree/Plants       

Fungi

  roots/branches     

mycelium

         fruit

mushroom

        seeds

spores

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Although we usually only notice mushrooms, they are the tip of a fungal iceberg. In one cubic inch of soil there can be 8 miles of mycelial threads that are 1 cell thick.

There are two main types of mushrooms: saprophytes that directly decompose organic matter and mycorrhiza that form symbiotic associations with plants. Mycorrhizal fungi receive access to carbohydrates from the host plant in return for increased water and nutrient absorption for plant hosts.

While mycorrhizal fungi are often said to live in symbiosis with other species, recent evidence shows the important role they play in balancing the overall health of the ecosystem rather than favoring particular species. One experiment showed when a Douglas fir was shaded by researchers, dyed sugars were transported by mycorhizal fungi away from a nearby birch tree in full sun to the shaded fir, compensating for the sudden increase in shade. Another species of mycorhizal fungi was observed eating springtails (a soil-residing insect smaller than 6 mm) and transporting the nitrogen from the insect to Eastern white pine trees, which gave the pines an estimated 25% of their nitrogen. In another interesting study, researchers observed mycorrhiza sharing nitrogen from nitrogen-fixing alders with nearby pine trees. 

Home Cultivation

Since mycorrhiza often require a particular environment to associate with plants they can be difficult to cultivate. Chanterelles, morels, and truffles are common edible mycorrhizal fungi. Most of these are collected from the wild, except for some old European truffle orchards that have proven difficult to duplicate.

There are many edible mushrooms that grow wild all over the world. Yet just like with plants, most known mushroom species are simply inedible with a few mildly poisonous and a handful fatal if ingested (mushroom poisoning requires ingestion). A good resource to begin with besides a local field guide is the “Mushroom Hunting and Identification” subforum at http://shroomery.org/forums, where pictures of questionable mushrooms can be posted and identified by experienced mycologists and hunters.

Agaricus bisporus is the most commonly consumed mushroom in the US, sold under the name of portobello, baby bella, cremini and button mushroom, usually grown on composted manure. Shiitake, oyster and enoki are some other popular mushrooms available in many US grocery stores. They are saprophytes growing directly on dead organic matter like fallen wood on the forest floor. They are primary decomposers that favor mostly deciduous, non-aromatic hardwoods like oak, maple, sweetgum, poplar/aspen, and alder.

Like many other hobbyists, amateur mushroom growers continually develop new techniques. Many of these techniques require minimal resources so mushrooms can easily beproduced without specialized equipment on a small scale. The basic steps to cultivate all saprophytic species of mushrooms are:

1. Start with spores or a culture of mycelium
2. Expand the culture/germinate the spores on spawn
3. Provide nutrients for fruiting mushrooms with a substrate 

culture of mycelium is typically used for cultivation to keep desirable genetic traits. This is similar to vegetative propagation and grafting for plants. Starting with spores can sometimes result in unpredictable results. It would be like trying to grow an apple tree from seed.

Creating spawn is similar to creating a starter or “proofing” yeast in homebrewing or bread baking. This gets the fungi of your choice a head start against competitor microorganisms. Paul Stamets says this is when the mycelium is “running” and can easily outgrow competitors. Thus, work is saved from having to create a sterile environment for your fungus of choice to thrive. Sawdust and various seeds like rye and millet are typically used for spawn.

When the spawn is 100% colonized by the fungus, it is ready to be introduced to a substrate. This involves mixing the spawn with organic material like compost, woodchips or logs, which will provide the necessary nutrients for the mycelium to fruit by forming mushrooms. Supplements like alfalfa or wheat bran can be added to speed up and allow for larger fruit formation. 

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Jars of the bird seed colonized by oyster mycelium, ready for spawning to substrate.
 

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“Spawning” or “inoculating” the substrate with spawn. In this case, the spawn is layered between paper and cardboard, which will provide nutrients for phoenix oyster mushrooms to fruit.

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About one month later a large flush or fruiting occurs.

Oyster mushrooms are often recommended to beginners of edible mushroom cultivation.  As demonstrated above they can grow on a wide range of substrates with low nutrients as long as they have a supply of cellulose. They can even grow on paper or cardboard.

Fungal learning

For my first grow, I gathered some small pieces of cardboard and saved a bunch of junk mail. I inoculated jars of bird seed to use as spawn and then layered the spawn with the substrate of junk mail and cardboard. After two months I harvested about 5 pounds of oysters from two bins of paper and cardboard. More details and pictures of my first attempt are at http://wcpermaculture.org/using-trash-grow-gourmet-mushrooms.

After the oyster mushrooms fruited five or six times and petered out, I ended up with a few sheets of very tightly bound paper held together with mycelium. While tough, these sheets of paper have already started decomposing. Previously there were just numerous, small pieces of junk mail and cardboard. This is perfect for sheet mulching and if top-dressed with fresh straw or hardwood chips will usually continue fruiting. One problem with oyster mushrooms is they fruit, mature and decay very fast. So if they are not in a place one frequently visits they can be hard to catch when ready for picking.

My next experiment was to attempt to inoculate sheet mulch directly with bird seed colonized by oyster mycelium. In between two layers of cardboard, I spread colonized bird seed and top-dressed with grass clippings (no fresh straw or hardwood chips was available to me at the time). Five holes were cut in the sheet mulch to the soil and sweet potato slips were planted. In about two months, when the oyster mycelium would be ready to fruit, the sweet potatoes were providing the necessary shade for the oyster mushrooms. However, due to contamination—likely from the seeds in the grass clippings and an insufficient amount of spawn—I only saw a single harvest from this experiment. There were no repeated flushes or fruitings like from the previous grow. Seeds are easily colonized by fungi, hence their usage for spawn to expand mycelium. This also means seeds easily contaminate if not sterilized. This is why straw, not hay, is popular for oyster cultivation (alfalfa hay is an exception and is sometimes used in small amounts to provide a nitrogen boost).

I was fortunate enough to find a tree crew thinning oaks near powerlines down the road and directed them to dump their wood chips at my place. These were far from sterile as they were actually sitting outside for a month while the spawn was being colonized. About three weeks after I finally spread about 6 quart jars of spawn between woodchips I was surprised to find 1/2 lbs of oyster mushrooms fruiting. This outdoor patch continued to fruit after every rain for another month. The sheer amount of grain spawn had overpowered any other competing microorganisms on the unsterile wood chips. These mushrooms were much more flavorful than the oysters grown on paper.

If one has access to a wood lot of hardwoods, shiitake and reishi mushrooms can be used to obtain additional yields from thinned and fallen trees as well as more quickly cycle the logs to soil. In an area without prevalent hardwoods it can be difficult to locate suitable logs for cultivation as the ideal time for log inoculation is 2-3 weeks after being cut. Yet both species of mushrooms are easy to cultivate and there is much published research on their numerous immune-system stimulating health benefits.

About four months ago a water oak was blown over on our property. I finished it off and after two weeks cut it up into 3 feet sections. I then drilled a small hole every 3 inches all the way around the log in a checkerboard pattern. I ordered shiitake sawdust spawn for a small fee from Fungi Perfecti (fungi.com) and inoculated each hole in the logs with spawn then sealed the holes with melted beeswax. Once inoculated, the logs will continually fruit in a shady location for about two years with only the occasional watering during dry periods. Surplus can easily be sold for about $9/pound. Local, fresh shiitakes are difficult to come by—I have never seen any in good, fresh conditions at a grocery store before. I had no problem lining up a nearby health food store to buy all surplus that my logs produce.

My next grow will be with two saprophytes—garden giant (Stropharia rugoso-annulata) and elm oyster (Hypsizygus ulmarius). They reportedly break down organic matter so quickly it increases the yield of nearby vegetables in a straw or woodchip-mulched bed. In eastern Europe, the garden giant has reportedly been grown with corn in this manner for some time. If another reason was needed to grow the garden giant, a recent study found they also consumed nematodes.

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Stropharia rugoso-annulata growing under straw in an annual vegetable garden

Please feel free to contact me with questions or feedback via http://wcpermaculture.org/contact


Resources

Shroomery Forums - http://www.shroomery.org/forums/ - The largest online community of fungi enthusiants. I’ve found the “Gourmet and Medicinal Mushrooms” and “Mushroom Hunting and Identification” subforums to be particularly helpful.

Fungi Perfecti – http://fungi.com – Company started by popular mycologist Paul Stamets. They offer a range of helpful cultivation items and wide selection of books. I’ve found shipping sometimes to be slow and slightly higher pricing than other sources.

Spore Works – http://sporeworks.com – Cheaper source of spawn and tools than Fungi Perfecti. Popular with shroomery.org members.

Field & Forest –  http://www.fieldforest.net – I only ordered wax from them before but they have a wide range of cultures. Their prices seem to fall somewhere between FungiPerfecti and Spore Works.