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Deep Winter Greenhouses


Photo credit: Prototype Deep Winter Greenhouse designed by researcher Daniel Handeen of the University of Minnesota College of Design Center for Sustainable Building Research.


Latest News | What is a Deep Winter Greenhouse (DWG)? | Deep Winter Greenhouse Resources

Latest News

Deep Winter Greenhouse (DWG) Research Convening held November 4, 2016

As the RSDP and project partners prepare to build DWGs over the next two years, the time to start planning projects and research ideas is underway. On November 4, 2016 the RSDP hosted a research convening made up of current DWG producers, prospective DWG producers, UMN staff and faculty, and other stakeholders. This group shared their past research with each other and brainstormed ideas for projects to address current DWG production needs. View the 2 hour long presentation here, download the presentation (PDF), or check out the overview document to see a list of research and project ideas.


Learn the basics of RSDP's statewide DWG campaign in our Media Fact Sheet, and check out recent media coverage:

Stay Connected

Interested in exchanging resources and information with farmers, researchers, and community members interested in DWGs? Join the Deep Winter Producers Association (DWPA) Facebook group and like the DWPA Facebook page. To keep abreast of all of RSDP’s happenings, like us on Facebook (, follow us on Twitter (@RSDPMN), and subscribe to our newsletter.

What is a Deep Winter Greenhouse?

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

DWG Research Convening 2016
At this event, the Regional Sustainable Development Partnerships brought together UMN faculty, researchers, and students together with DWG producers to discuss past research and identify new research needs. View presentations from RSDP statewide director Kathy Draeger, RSDP Sustainable Agriculture and Food Systems director Greg Schweser, DWG producer Carol Ford, DWG producer Jim Dontje, DWG producer Kim Erickson, UMN Soils professor Carl Rosen, and UMN Horticulture professor John Erwin.

To watch the seminar click here or download the presentation (PDF). The 2016 Deep Winter Greenhouse Research Convening summary provides an overview of the research convening and provides a list of project ideas and research topics that participants identified.

DWG History, Design, and Future Aspirations
University of Minnesota College of Design researcher Dan Handeen presents to the Minnesota Renewable Energy Society on the history, design, and future aspirations of the Deep Winter Greenhouse project (September 2016).

To watch the presentation click here.

DWG Research Seminar 2015
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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