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.
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 latitude 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 acts as a heat battery. Without additional lighting, DWGs in Minnesota can be used to grow cold hardy crops that thrive with minimal light providing year-round production capacity for small scale farmers and gardeners. Crops well suited to DWG production include a variety of lettuces, herbs, brassicas, asian greens, and sprouts.
Deep Winter Greenhouse Resources
Statewide Prototype 2.0 Initiative
Statewide Prototype 2.0 Initiative
As part of a statewide initiative to advance DWG research and outreach, the University of Minnesota Extension Regional Sustainable Development Partnerships (RSDP) are supporting the construction of five DWGs using an updated design from the College of Design's Center for Sustainable Building Research. The five DWG 2.0s are being built with the following community partners:
- Organic Consumers Association in Finland (ribbon cutting February 18, 2017)
- Bemidji Community Food Shelf (ribbon cutting September 30, 2017)
- Grandpa G's Farm in Pillager
- Alternative Roots Farm in Madelia
- Lake City Catholic Worker Farm
Support for the statewide initiative is provided by University of Minnesota programs and a consortium of agriculture lending banks:
- University of Minnesota Extension
- Institute on the Environment
- MnDRIVE Global Food Ventures
- AgriBank Farm Credit Bank
- Compeer Financial
- AgCountry Farm Credit Services
Mattson MacDonald Young provided the structural review and structural plans for the statewide DWG campaign prototype.
Design & Construction
Starting a DIY Deep Winter Greenhouse Operation on a Budget (PDF)
For those who are looking to build a DWG on a budget, this report explains some of the techniques used by experienced DWG producers to build your own affordable structure for winter production.
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.
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.
Deep Winter Greenhouse Crop List (PDF)
This is a list of crops that producers have found to work particularly well in the DWG system.
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.
DWG Research Convening: Nov 4, 2016
Current and future DWG producers, RSDP staff, UMN faculty, students, and researchers discuss past projects and research and discuss future research needs.
Watch the seminar 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.