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Fostering Sustainability and Innovation in Agriculture
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Electrical Engineer Leverages Knowledge of LEDs and Green Tech to Sustainably Grow Organic Mushrooms

February 6, 2013 |

Shiitake mushrooms growing under LED light. Photo Credit: Mountain Mushroom Farm.

Being an organic shitake mushroom farmer in Malo, Washington isn’t the easiest thing to do which is probably why electrical engineer, master electrician and green technology inventor Marc Keith decided to do it. Along with his wife Vivian, Keith runs Mountain Mushroom Farm, which he claims is one of the most self-sustaining low energy organic farms around. He may be right, and he would know, having built the farm from the ground…well, underground, up.

By carving out a chunk of his hillside and burying a shipping container, Keith was able to begin an underground shitake mushroom farm on his mountain property. His design choices and mathematical mind ensured the supports were perfectly aligned and the retaining walls perfectly sealed. His desire for a better, greener world meant he placed an acre wide berry patch (supplemented with manure from the local llama farm) on top of the mushrooms to ensure his bees had a nice supply of local pollen. Once the shipping container and cover soil were in place, it was time to build that energy efficient mushroom factory.

The entrance to Mountain Mushroom Farm. By carving out a chunk of his hillside and burying a shipping container, Marc Keith was able to begin an underground shitake mushroom farm on his mountain property. Photo Credit: Mountain Mushroom Farm.

The farm’s construction began back in 2009, and after a few weather related building setbacks, has now been producing high quality shitake mushrooms for the local market for three consecutive years. Contrary to popular belief, most mushrooms need adequate light to grow, not to mention heat and water. But because Keith wanted his farm to be an exercise in planet healing projects as well as profits it was all a bit more than switching on the lights and turning on the tap.

The farm is lit with low energy LED light strings that provide just enough luminosity for growth. Couple that with the passive fresh air design of the underground unit and Keith managed to create the first commercial all LED mushroom farm at the same time as he reduced his farm’s electrical use by 95 percent.

“The structure of the mushroom farm is in complete ground contact on five sides for efficient geothermal heating in winter and cooling in summer,” shares Keith. “The ground maintains 55F to 60F, which is perfect for mushrooms. Excess heat is absorbed by the walls during warm months and returned to the grow areas during the cold weather months.”

Transporting the mushrooms to the area stores is the only use of fossil fuels in Keith’s mushroom farming operation. Keith designed and built a wood fired steam generator to supplement the geothermal effects of the farm’s structure and location. The generator reduces reliance on the national grid, is used to regulate temperature in the grow room, to warm the air in their hydronic heat exchanger and to create steam to aid in the spore sterilization process. The generator is fueled with wood left over from forest fires, which as Keith explains are: “…already in the process of releasing their CO2 into the atmosphere. No additional CO2 is released by burning this wood. No live trees have ever been cut down to supply our mushroom farm with sawdust and firewood.” Sawdust is used to create the substrate or grow bed for the mushrooms.

Rain is the main water source for the farm. Water is collected from rooftops and in rain barrels in the summer to supplement the snow that provides nourishment during the winter. By building the mushroom farm on a slope, the rain and snow water run through the underground farm and come out onto the family’s vegetable garden.

Creating local produce is only one of Keith’s goals. Showing people how they can cultivate crops while supporting the local environment is a key part of Mountain Mushroom’s ideology. As board supervisor of the local conservation district, Keith likes to take what he learns on the farm and use it to help his community. Recycling the leftover mushroom substrate has become a big part of Keith’s business.

Living in the desolate mountains of Washington has its advantages as a grower but it also has its problems. The many pioneer era outhouses that dot the landscape are a source of pollution and a contaminant to local ponds and rivers. That was until Keith got out his leftover substrate.

“…The stench from this seepage is overwhelming, and the resulting algae bloom is threatening the fish and other wildlife,” explains Keith. “After just three years of placing some of our spent sawdust substrates into several areas of this seepage, the stench is completely gone, and there is only a small amount of algae that forms during the hottest months.”

Mushroom mycelium eats unwanted bacteria as it returns to the earth not only masking the smell of the century old sewage but actually eradicating the issue entirely. The sawdust used to produce the mushroom substrate is waste from a local lumber mill. Working with, rather than against, the local environment has reduced waste and extended the usefulness of the farm.

Soil erosion and conservation can be devastating to microorganisms, native plants and the quality of local crops. Keith found a way to stop erosion and actually improve the local soil. By scattering the spent substrate over the eroded hillsides of his community, Keith and his team, as part of the conservation district funded bank stabilization project, have reduced erosion and encouraged new growth.

“Unstable slopes can have straw or sawdust (or any local suitable waste material) spread over them and then inoculated with mushroom mycelium from spent mushroom substrates. This mushroom mycelium will colonize the organic matter on the surface and then hold it tightly together until vegetation can get established. As it degrades the sawdust, it also releases fertilizer to the new vegetation, creating a true micro-environment,” shares Keith.

Keith began the mushroom farm as a venue for his green engineering experiments and a way of sharing his knowledge of fungus cultivation. Keith has grown mushrooms as a hobby since 1972 but only began thinking commercially in the last ten years. Royalties from his video series: “Let’s Grow Mushrooms!” and crop sales combined with low overheads and self-sustaining practices are what make Mountain Mushroom Farm so special. It shows you that not every organic farm must produce leafy greens or even operate above ground to be successful.

Saving the landscape, improving the soil, creating natural fertilizer and livestock feed (oyster mushroom substrate), consuming unwanted bacteria and reducing waste from three local businesses is just another day at Mountain Mushroom Farm. For Keith, farming and research for bettering the environment go hand in hand. His latest venture takes place in the laboratory where he is working with conservationists to develop a mushroom that will grow on an evasive plant species. It seems mushrooms really are one of nature’s never ending gifts and it seems Marc Keith and Mountain Mushroom Farm have the gift of making mushrooms work for all of us.


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