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Deep Winter Greenhouses

Advisory committee reviewing Deep Winter Greenhouse applications
RSDP received more than 40 applications in response to the statewide Deep Winter Greenhouse (DWG) campaign. The Partnerships are collaborating with producers and organizations throughout Minnesota to build five DWGs - one in each RSDP Region. The campaign is made possible by support from a consortium of farm lending banks, including AgCountry Farm Credit Services, AgriBank, AgStar Financial Services, and United FCS. An advisory committee is now reviewing applications.

The campaign invited farmers, community members, schools, organizations, and businesses to apply to partner with RSDP to build a DWG on their property. In exchange for technical assistance and funding, partners agree to participate in University research and outreach events for a period of three years. Each DWG will be built according to a prototype design developed by the Center for Sustainable Building Research, and will provide a platform for others to learn about the technology.

Applications are currently being reviewed by an advisory committee made of representatives selected by RSDP with expertise in agricultural production, energy efficiency, clean energy, and community development. Committee members include a representative from each of RSDP's five Regions as well as three members representing University of Minnesota Extension and United FCS. One applicant will be selected from each RSDP region. Applicants will be notified in mid-June. For additional information on RSDP's statewide DWG campaign, contact Greg Schweser at

A Deep Winter Greenhouse (DWG) is a passive solar greenhouse designed to dramatically limit the amount of fossil fuel required to grow crops in northern latitudes. DWGs are oriented east-west with a south facing glazing wall specially angled depending on the latitude of the greenhouse to maximize solar energy on the shortest day of the year. Solar energy is stored in an underground thermal mass made up of an insulated rock bed that is covered with soil. Perforated drain tile that is laid out in the underground rock bed and distributed through the air through vents and fans that connect the air to the underground heat storage. Crops can be planted directly into the soil and through a system of suspended planters.

DWGs are utilized to grow cold hardy crops that thrive with minimal light throughout the middle of winter providing year-round production capacity for small scale farmers and gardeners. Crops well suited to DWG production include a variety of greens, herbs, broccoli, broccoli raab, kale, collards, Chinese cabbage, bok choy, and pea shoots. While fruiting crops like tomatoes, peppers, green beans, etc.. are not commonly grown in DWGs there is still lots of room for innovation and experimentation.

Deep Winter Greenhouse Resources

Design & Construction | Economics & Marketing | Production | Educational Videos | Connect with others

Design & Construction

Northlands Winter Greenhouse Manual
Carol Ford, Chuck Waibel
This is a link to the order form for the Northlands Winter Greenhouse Manual. This book provides detailed and easy to read construction specifications for building a Deep Winter Greenhouse in northern climates as well as production techniques for successfully growing crops.

Cold Climate Greenhouse Resource manual (PDF)
This guidebook highlights the successes and lessons learned by growers across the Midwest who have designed and built cold-climate greenhouses to grow produce during the winter with minimal reliance on fossil fuel-based heat.

Solar Greenhouses
ATTRA, National Center for Appropriate Technology
This site contains a large amount of useful information about solar greenhouse design.

Deep Winter Greenhouse Presentation (PDF)
This lightening talk presentation demonstrates the basic principles of Deep Winter Greenhouse technology using an 8' by 11' model.

Economics & Marketing

Deep Winter Greenhouse Enterprise Analysis (PDF)
This research report examines the ability of Deep Winter Greenhouses to be viable business models. Results are based on analyses of seven Deep Winter producers in Minnesota in the winter of 2014/2015.


Soil Nutrients in Organically Fertilized Potting Media under Greenhouse Conditions (PDF)
This poster displays results of analyses of various potting soil mixes for the common DWG crops of mizuna, arugula, and giant red mustard.

Day and Night Temperature Effects on Kale Morphology and Photosynthesis (PDF)
This poster highlights research results on day/night temperature effects on kale plant growth.

Deep Winter Greenhouse Producer Bios (PDF)
These case studies provide the stories of three different Deep Winter Greenhouse producers. Learn what inspired them to build a DWG, what drives them to produce, and learn lessons that only those with experience can tell.

Reinventing Year Round Local Food Production in Minnesota -- Mid Term Project Report (PDF)
This report highlights progress on a variety of research projects underway to look at the potential to maximize winter vegetable production. Results of analyses of day-night temperature effects on plant growth; vitamin c content of different fertilizer mixes; light response curves of kale; and vitamin c depletion rates are included.

Winter organic wonderland: Evaluating organic fertilizers for greenhouse production (PDF)
This poster was presented at the Midwest Organic and Sustainable Education Services 2015 annual conference. The poster highlights results from trials that examined the performance of different fertilizers used in winter production.

Educational Videos

November 4, 2015 Deep Winter Greenhouse Research Seminar
This research seminar hosted by the UMN Regional Sustainable Development Partnerships highlights recent projects investigating Deep Winter Greenhouse technology. Greg Schweser provides an overview of RSDP Deep Winter Greenhouse projects, Liz Perkus discusses horticultural research into crop production, and Dan Handeen explains building performance and operation of this unique passive solar design.

To watch the hour long seminar click here or download the presentation (PDF).

Deep Winter Greenhouses
On the Road, Southwest Minnesota, University of Minnesota
A quick overview of Carol Ford's DWG that presents the general concept of the technology.

Connect with others

The Western Chapter of the Sustainable Farming Association of Minnesota is hosting the Deep Winter Producer Association networking group.

Like the Deep Winter Producers Association's Facebook Group
This Facebook group will enable those who are interested and/or operating Deep Winter Greenhouses to connect, post questions, and network.

Like the Deep Winter Producers Association's Facebook Page
Receive posts from the monitors of this Facebook page to keep up with current DWG news.


For more information, please contact Greg Schweser
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