Mushroom growing techniques have been developed to a high degree of technical efficiency. Proven methods exist for growing many kinds of edible or medicinal species. Mushroom growing kits can be purchased ready to be set up in an appropriate environment to produce mushrooms. Commercial quantities of mushrooms are grown using large scale production methods.

Mushroom Spawn Production

Before mushrooms of any kind can be grown, a quantity of starting material called “spawn” must be produced. Spawn is a mass of the white fuzzy mycelium of a fungus grown in a form suitable for inoculating a large quantity of substrate on which the mushrooms will be produced.

Grain spawn is prepared by inoculating sterilized rye grain in jars, with a pure mushroom culture. The mycelium grows throughout the grain and the spawn is expanded to any desired quantity by using the colonized grain to inoculate still other jars of grain. This type of spawn is convenient for starting mushrooms that grow on compost.

Dowel spawn is produced by inoculating bags of sterilized wooden dowels. When fully colonized, the dowels are driven into holes drilled in logs, or the dowels can be added to bags of wood chips or sawdust. Dowel spawn is used to culture wood-inhabiting species.

Growing Mushrooms in Compost

The classic commercial button mushroom (Agaricus bisporus) and the larger portabello (which is the same species allowed to get well past the button stage) is grown in tremendous quantities on mushroom farms around the world. Since the natural habitat of its wild predecessors was in pastures, this species is grown on a substrate of horse manure compost. Other species grown on compost include Coprinus comatus (shaggy mane) and Lepista nuda (blewit).

A number of variations on preparing mushroom compost exist, but two basic formulas are (1) horse manure, cotton seed hulls and gypsum, and (2) chicken manure, wheat straw and gypsum. The compost is inoculated with spawn and the spawn is allowed to completely colonize the substrate. Production of mushrooms is initiated after a peat-based casing layer is spread on top of the colonized compost.

Growing Mushrooms on Logs

Reishi mushrooms (Ganoderma lucidum), shiitakes (Lentinula edodes), hen of the woods (Grifola frondosa), lion’s mane (Hericium eriniceus), and oyster mushrooms (Pleurotus spp.) are all wood-decomposing fungi suitable for log cultivation.

Most species prefer hardwoods such as oak, maple, elm, cottonwood and alder, although a few species do well on conifer wood. The logs are best cut just before winter when their sap content is highest. Logs should be allowed to age for a month or two, but should be used before they dry out. Any size of log should work, but if the logs are big and heavy they take longer to colonize and are difficult to transport and handle. A length of about a meter and a diameter of 10-30 cm is good.

Dowel spawn is driven into holes drilled into the logs. The holes are sealed with wax to keep the inoculum from drying out before the fungus can become established in the wood. Under the best of circumstances, the logs will not be ready to produce mushrooms for six months, with a year or more being more typical. When the logs begin to show mycelia on their cut ends, they are close to being ready for fruiting.

Fruiting is initiated by soaking the logs in cold water for twenty-four hours followed by further incubation in high humidity with fresh air. Logs can produce flushes of mushrooms periodically for several years.

Growing Mushrooms in Sawdust and Wood Chips

Mushroom species that do well in logs can also be grown in bag culture using the same kinds of woods. Dowel inoculum, liquid spawn, or grain spawn is added to bags of sawdust and/or wood chips and thoroughly shaken. After two or three weeks, once the mycelia have grown throughout the wood, the bags are shaken again and incubated an additional couple of weeks until the substrate is fully colonized.

Then the bags are usually slit open and soaked in cold water for a day and incubated in high humidity with fresh air exchanges. Mushrooms are produced in as little as five weeks with this method and two or three flushes, with rest periods in between, can be achieved before the nutrients are used up in the wood.

Many mushroom growing kits come with a substrate of sawdust and/or wood chips. These kits are easy to set up since they come ready to produce mushrooms in a relatively short time once the correct conditions are established.

Other methods of mushroom growing exist for research or laboratory purposes, but the methods outlined above are the ones usually used by both commercial and hobby mushroom growers.

References

Stamets, Paul, and Chilton, J. S., 1983, The Mushroom Cultivator, Agarikon Press, Olympia, WA

Stamets, Paul, 1993, Growing Gourmet and Medicinal Mushrooms, Ten Speed Press, Olympia, WA

Note: This article was originally published at Suite101.com.

Figure 1. A Vertical Farm Concept (iied.org/flickr.com)

I recently read The Vertical Farm, Feeding the world in the 21st Century, by Dickson Despommier (2010, Thomas Dunne Books, St. Martin’s Press, New York, NY) and I also got a chance to chat with him on the phone to get some information for an article I wrote for a magazine. Dr. Despommier is a microbiologist and a driving force behind the vertical farming (VF) movement. Vertical farms are urban structures designed for food production. I highly recommend the book to get the full scoop or you can also learn more at The Vertical Farm website. Figure 1 is probably enough to give you some idea of what one might look like. Things are just getting started in the VF world right now but several projects are under way around the globe.

However, I got to thinking, how could mushroom growing fit into the VF scheme of things? The carbon dioxide/oxygen linkage between plants and fungi seems like it is ready-made to play a role in any vertical farm intent on maximizing efficiency. There could be some favorable humidity conditions available in a VF building using hydroponics that could be taken advantage of as well. I visualize something like this:

• Mushroom spawn can be produced in a controlled environment within the VF building.
• The CO₂ laden air from the spawn room can be slowly vented into the plant growing areas to enhance photosynthesis.
• If Agaricus is the species in cultivation, it could be grown in the inner parts of the structure since there would be no need for light.
• Light-requiring species could be grown in bags and moved about on rolling carts into areas of light when it was time to induce fruiting.
• When it was time to induce a flush of mushrooms the more oxygen rich moist air from the plant environment could be circulated into the grow room, or as mentioned, the spawn bags could be moved into or near to the plant section.
• Mycelium is already being used for CO2 supplementation by some growers (see Figure 2).

Figure 2. Exhale Bag for Carbon Dioxide Production (Philip McIntosh)

These ideas are very general I realize, but they do layout a framework to be pursued. After I had thought about this, I ran across a brief notice during my article research about a VF project in Manchester UK that plans to include mushroom growing. Details on that project are sketchy so I am not sure to what extend the mushroom growing will be integrated into the overall design.

I figured others have probably though of this idea too, so a quick web search reveals a couple of things, but they are mostly conceptual and no one to my knowledge is actually putting any sizable mycocultural modules into a VF operation at this time.

One interesting concept is SPORE v2 described at ARKFAB (Figure 3). It is a design for a specialized growing facility but I think it is a stretch to call it a vertical mushroom farm. It’s more of a really cool design for a regular mushroom farm and it’s not very vertical. Since it is designed to be a stand alone unit, it is not really along the lines of how I envision mushroom farming being integrated in to a VF structure. But, could the SPORE v2 be installed somewhere within a larger VF building? It sure looks like it could. Tragically, the founder of ARKFAB recently died in a motorcycle accident and email messages are bouncing, so for now I can get no further information on SPORE v2.

Figure 3. The ARKFAB SPORE v2 design (ARKFAB)

It looks like Plant Chicago has the right idea. Plant Chicago is a nonprofit dedicated to promoting sustainable food production, entrepreneurship, and building reuse through education, research and development. According to the diagram (Figure 4) they appear to be putting some thought in to exactly how mushroom farming would fit into an overall plan to include hydroponics as well as aquaponics. It’s a work in-progress, and according to Melanie Hoekstra, Operations Manager at The Plant, the substrate has been inoculated but no mushrooms have appeared yet..

There are plenty of references to growing mushrooms “vertically” in bags, or stacked vertically on shelves, or vertically on a wall, etc. But, there seems to be very little information about anyone who is really putting serious thought and effort into true vertical mushroom farming with the same scope and breadth of vision as Dr. Despommier lays out in his book. So, the question remains—who will build the first truly integrated mushroom growing operation in a vertical farm?

Figure 4. Plant Chicago Design Includes a Mushroom Facility (Plant Chicago)

Many years had gone by and nothing seemed to have come from the company’s efforts. My attempts to contact some of the people that I knew were involved in the company (Eric Danell for example) went unresolved.

Then, a couple of months ago I received this comment on the original post:

My name is Niclas Bergius. I’m a Swedish biologist that was employed by Cantharellus AB from 1997-2000. Today I work with the famous matsutake mushroom: http://www.goliatmusseron.blogspot.com/

The technique from Cantharellus AB was transformed to the matsutake mushroom during early 2000. This company (Matsutake AB) does still exist but is resting right now.

If you write to me I can tell you the whole story about Cantharellus AB.

Bergius has been involved in research in Sweden regarding wild Matsutakes and he was participated in the work reported in the article published in USA Today, Rare and costly Japanese mushroom found growing wild in Sweden.

Here is what else I found out after further communication with Niclas.

There’s Not Enough Money in Chanterelles

Figure 1. Biologist Niclas Bergius with a Swedish matsutake

I was pretty sure Cantharellus AB was out of business because of a legal document I found (in Swedish) on the web indicating the company had gone into bankruptcy (or a similar state).

As it turns out, the methods and techniques used by the company were expensive. So expensive that they could not make it economically viable. Why not? Because chanterelles do not have sufficient commercial value to generate the required return on investment that the company was making.

“The problem with cultivation of the golden chanterelle was the low price of the mushroom,” Niclas told me. “Since the technique for artificial cultivation is labor intensive and quite complicated the cost was high and could not be paid for by the amount of money brought in.”

Enter Matsutake AB

Perhaps the management had this figured out sometime late in the 90′s because in 1999 the management of Cantharellus AB decided to form a sister company—Matsutake AB. Fresh top grade matsutake (Tricholoma matsutake) goes for up to $4,000(US) a kilogram in Japan during a season with low production. The standard price for quality imported matsutake in Japan is about $200 per kg. The price for golden chanterelle in shops in Sweden is only about $35 per kg. So, theoretically it would be easier to make a profit by cultivating matsutake instead of chanterelles.

Figure 2. Matsutake mushroom cultivated in association with pine trees in the Matsutake AB laboratory

The company made good progress in cultivating matsutake by 2003, which unfortunately was when luck ran out and the company had serious financial difficulty. “We just could not get new money to the company for a large scale cultivation,” explained Bergius.

Cantharellus AB no longer exists and since 2004 Matsutake AB has has been operated by Niclas Bergius with minimal activity. He plans to reboot the company as as soon as enough new money becomes available to begin a large scale effort. Matsutake AB owns the rights to the applicable technique invented by Eric Danell.

At the moment, Bergius is the only person working on a regular basis at the company, although he hires some friends to assist him during the field season. He hopes to start large scale business again sometime during the next 3-4 years.

Interestingly, Matsutake AB has focused on indoor cultivation, although Bergius suggests his methods could be used outdoors as well. The process is sped up by doing it indoors, which could be a major factor in any commercial application. Bergius has not revealed any details of his work, but was kind enough to share a couple of photos (Figures 1 and 2)

And, in case anyone is looking for Eric Danell, he is now living in Thailand and working as a consultant to a greenhouse company. According to Bergius, he is not currently involved in any mushroom research.

Yep. The folks at Wired have set up a Mushroom Box Mini Growing System, a small mushroom growing chamber, and have been watching mushrooms grow. But why would they consider such a cool thing to be dangerous? It might have something to do with the kind of mushrooms they intend to grow.

At their website they also have a video of how the system was set up. It looks like nothing more than a small amphibian enclosure or aquarium that just has a some spawn put into it. Actually, that’s not a bad idea in comparison to most mushroom kits that offer a plastic bag tent for a humidity chamber.

Japanese farming lore has long observed that plentiful mushroom harvests tend to follow thunderstorms. Now researchers at Iwate University in northern Japan have confirmed the legend, finding that some mushrooms more than double their yields when jolted by electricity.

The researchers used “artificial lightning” to stimulate the fungi into producing greater yields. Shiitake and nameko mushrooms were subjected to the treatment with reportedly excellent results. Sounds like it could have commercial applications.

The above article, which appeared at the Mother Nature Network, takes its information from a report Lightning Makes Mushrooms Multiply published by National Geographic, which includes important additional information. In this report, the scientists speculate on why the fungi may respond to electric charges in this way. It also clarifies that the fungi were not zapped with “lightening” per se, but were stimulated by applying high-voltage pulses to mushroom logs.

As part of a four-year study, scientists in northern Japan have been bombarding a variety of mushrooms in lab-based garden plots with artificially induced lightning to see if electricity actually makes the fungi multiply. The latest results show that lightning-strength jolts of electricity can more than double the yield of certain mushroom species compared with conventional cultivation methods.

In all, ten mushroom-forming species have been used in the experiments and crop plants are also undergoing testing.