Extending Growing Seasons in Cold Climates: Greenhouses Powered by Clean Energy

Many places in Minnesota have found a way to extend the warm growing season into the colder winter months. This isn’t that surprising, greenhouses have been around, by some accounts, since the time of the Roman Emperors, and their objective remains the same: providing fresh, local produce for people to enjoy at any time of the year.

Originally constructed to serve the wealthy and powerful, today, anyone with the proper space and tools can construct a greenhouse. Through several greenhouse projects the Clean Energy Resource Teams have had the pleasure of working with people passionate about incorporating energy efficiency and renewable energy into their operations, ranging from local commercial endeavors to school projects. Below are introductions and links to several case studies for greenhouse projects found in the state of Minnesota.

Biofuel and Food Greenhouse Facility at Silver Bay Eco-Industrial Park
They’re creating jobs by producing organic food and renewable fuel. The main inputs are fish feed, electricity, heat, and water, which are derived from locally-produced algae and biomass, and readily-available wind and rain. The main outputs are fish (12,000 pounds of tilapia per year), organic produce (starting with lettuce, basil, cilantro, parsley, sprouts, and mushrooms), and algae (oil extracted for biodiesel and remains fed back to fish).
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Watch a video about the original groundbreaking, interviewing project partners and local leaders in Silver Bay and surrounding communities:

Whitewater Gardens Farm’s Geothermal Greenhouse
Sandy and Lonny Dietz of Altura, Minnesota have been supplying produce to local residents, restaurants and food co-ops for years. However, in 2007 they wanted to explore options for extending their growing season using a greenhouse. They also wanted to find an environmentally-friendly way to heat it. A SE CERT grant allowed them to conduct a feasibility study that led them to install a ground source heat pump in their greenhouse. So far, the results have been promising.
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Hazelnut Valley Farm’s Solar-Heated Greenhouse
Norm and Mary Erickson of Hazelnut Valley Farm retired and started a hazelnut farm in Lake City, MN. Their nutty adventures into the business of growing, harvesting, and processing the crop led them to install a solar-heated greenhouse with many innovative features. Norm and Mary also look forward to a future where their plentitude of hazelnuts, which are 60% oil, can be profitably converted into biodiesel.
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Willmar High School’s Solar- and Biomass-Heated Greenhouse
Beginning in 2007, students at Willmar High School in Willmar, MN decided that they wanted to fix up an old greenhouse, update it by adding renewable energy source to heat it and provide out-of-season produce for local school food services and food pantries. They asked the West Central CERT to help them out and were granted the funds to help install a solar water heater and biomass boiler, which keeps the inside of the greenhouse warm enough to grow produce all the way through the bitter Minnesota winters.
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Video about this project from our recent documentary, ENERGIZED: Communities Building Minnesota’s Clean Energy Future, released November 2011:

HUG’s Passive Solar Residential Greenhouse
For something residential instead of rural, take a look at the Hunt Utilities Group (HUG) sustainable building research facility outside of Pine River in central Minnesota. HUG’s researchers wanted to explore the possibilities of taking the greenhouse out of the garden and attaching it to the home. Paul Hunt, the Project Coordinator explains, “A greenhouse that is part of a residence seems to have a lot of functions going for it. It gathers huge amounts of solar heat in the winter. Even at night, it buffers the south side of the house from losing heat. It adds wonderful space to a house. It helps clean and humidify the air. It helps feed the occupants.” In order to monitor their work, HUG installed sensors throughout their structures in order to measure energy use and temperature so they can optimize the design of future projects.

ARTech’s Passive Solar Greenhouse
Back in 2008, 7th and 8th grade students at the Northfield School of Arts and Technology (ARTech) became inspired to build a greenhouse. They became enthusiastic supporters of the idea in part due to a meeting with some of the Willmar High School greenhouse creators at the biennial CERTs conference in St. Cloud, Minnesota. They applied for and received a grant from Southeast CERTs to fund the building of the project, which would eventually support life science classes as well as seminars on sustainable food production. As a result, one of the students involved explained that they had been able to learn about planning, time management, construction skill, reasoning and an appreciation for plants and how our own food is grown.

Pelletizing On-Farm Perennials to Heat a Greenhouse
In 2010, CERTs provided a seed grant to Pork and Plants LLC focusing on the biomass that can be harvested from native perennial grasses and wildflowers (also called “forbs”). While corn stover is already harvested for biofuel, growing corn is very energy intensive; unconventional biofuels such as prairie grass may help bridge the gap between sustainable farming practices and renewable energy. In addition, it provides an opportunity to create a locally-supplied fuel source for rural communities.
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Video about this project from our recent documentary, ENERGIZED: Communities Building Minnesota’s Clean Energy Future, released November 2011:

Badgersett Research Farm’s Off-the-Grid Greenhouse
On the cutting-edge research side of things, meet Phil Rutter of Badgersett Research Farms and his revolutionary “woody agriculture” practices. For over thirty years he has been hybridizing several varieties of woody plants: chestnuts, hazelnuts, hickory nuts and butter nuts without ever having to plow his land. This saves precious topsoil. Another remarkable thing about the farm is that it is completely off the grid; his greenhouse is powered by photovoltaic cells. “We estimate the greenhouse, which is deep earth sheltered glass and concrete, and designed as a 4 season structure, uses on the order of 1/50th of the energy that other commercial greenhouses do; including heating, cooling, and water management.”
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Solar Thermal Air Heat for High Tunnel Season Extension
Dallas Flynn and his wife raise vegetables and shitake mushrooms on a small farm just south of Frazee that they sell at a nearby farmer’s market. They are now using solar thermal air heat collectors to heat the soil and extend the growing season in high tunnel vegetable production. Read the case study and the presentation below to learn more about how this approach can work for you.

The Cold-Climate Greenhouse Resource Guidebook
The Cold-Climate Greenhouse Resource guidebook, released December 2013 from the University of Minnesota, will help growers to design and build an efficient greenhouse in which to grow and distribute fresh produce year-round. The guidebook shows that in spite of Minnesota’s short growing season and sub-zero winters, it is possible to grow fresh produce during long cold winters, without relying heavily on fossil fuel-based energy sources. The guidebook documents successes and lessons learned by small Midwest growers who are actively growing produce during the winter, using greenhouses they have built. The guidebook describes the architecture, materials, and building techniques these growers have used to design and build efficient, yet simple, cold-climate greenhouses.
Download the guidebook

The Northlands Winter Greenhouse Manual
The Northlands Winter Greenhouse Manual, released in 2009, provides answers for people who live in northern climates and are concerned about the quality, safety, availability, and price of food. Whether you are a farmer or consumer, urban or rural, interested in sustainable farming, energy conservation, nutrition education or economic development, this book contains inspiring information for you and your community. A passive solar greenhouse closes the gap in the growing season that winter has long occupied. This project was supported significantly from the Southwest Minnesota Sustainable Development Partnership board (then, West Central), part of the University of Minnesota Extension’s Regional Sustainable Development Partnerships.
Learn more about Deep Winter Greenhouses

The effect greenhouses can have on our lives is just now being explored. The way we get our food is changing in many respects. As more people become interested in locally grown food and explore organic farming practices, the use of greenhouses to provide a community or even individual homes with food is becoming more common. Projects like the ones described above are proof that greenhouses powered by renewable energy can be viable, environmentally friendly ways of providing food to people all over the state of Minnesota.

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