Spring through fall is a busy time of year for Brooke and John Knisley, owners of Alternative Roots Farm in Madelia. For most of the year, they are busy growing and providing certified organic produce to their local community. Like many farmers, their revenue depends on the growing season.
In Minnesota, this leaves little room for vacationing or hiking when the weather is nice. To Brooke and John, enjoying the outdoors is a quality-of-life issue. When they learned about the potential for Deep Winter Greenhouses (DWGs) to extend farmers’ income during the winter, they saw an opportunity to bring more balance to their work and family lives.
In 2016, Brooke and John applied to be one of five community partners across the state working with the University of Minnesota Extension Regional Sustainable Development Partnerships (RSDP) to build a DWG that would produce crops for University research and outreach. DWGs enable small-scale farmers to grow crops that thrive with minimal light year-round, and they’re good for the environment. Solar energy is stored in an underground rock bed, replacing fossil fuels as the primary heat source.
Southeast region partners Sarah and Paul Freid and Shay O’Toole of Lake City Catholic Worker Farm had similar hopes for extending their revenue stream. They sell produce to locals who come to the farm and to the Lake City Farmers Market, and wanted to produce veggies for their customers throughout the winter.
Other community partners in RSDP’s DWG research and outreach include Organic Consumers Association in Finland, Grampa G’s in Pillager, and Bemidji Community Food Shelf, which is growing produce for its customers. These five prototype DWGs – one in each of RSDP’s five regions – are built according to design specifications developed by researcher Dan Handeen of the College of Design Center for Sustainable Building Research (CSBR). University research at the five sites will tell us more about how to maximize production, minimize construction costs, and what grows best in these environments. The answers can enhance the quality of life of farmers and consumers alike.
“One thing that I think often gets overshadowed is the quality of life that DWGs can help effect,” Handeen said. “I love that this is really allowing people to improve their true quality of life.”
Suite of research projects
A suite of research projects is now underway at the prototype DWGs. Horticulture studies will help understand what leafy greens grow best in these environments and how to most efficiently use resources such as light and energy, seed, substrate mixes and, importantly, the grower’s time. This community-based research is being supplemented by horticulture trials on the St. Paul campus, where controlled growth chambers can simulate stressed conditions, such as extreme hot and cold.
“It can help us identify how these crops will respond to temperature extremes that might occur in the greenhouses,” said Greg Schweser, RDSP Statewide Director for Sustainable Agriculture and Food Systems. “In the end, researchers will be able to come up with specific recommendations for things like variety choice and seeding density in the DWG based on the way the greenhouses are acting.”
So far, trials suggest that lettuces, mustards and Asian greens such as Florence, Tokyo Bekana and Vitamin Green generally grow well.
“In the first year of trials, differences in light and temperature were found between the three [initial] DWG sites and within each DWG,” said Claire Flavin, a researcher in the Department of Horticultural Science. “We’re looking forward to this next season and the opportunity to work with all five sites. Learning more about the dynamics of these sites is important because environmental differences translate directly to the productivity of the greens in these spaces.”
Other research will look at the thermal mass that stores heat underneath the greenhouse. The University of Minnesota Solar Energy Laboratory is monitoring sensors that were installed in the rock bed by a student in the College of Science and Engineering. “It will tell us how much energy is being saved in the rockbed itself and also if there are improvements we can make in the design,” Handeen said.
Farmers interested in building a DWG need to understand how it could affect their bottom line, and that’s where enterprise analysis comes in. Extension Educator Ryan Pesch will help farmers estimate when their initial construction costs will pay off. “The enterprise analysis gives us a picture of the DWG business and how it cash flows,” Schweser said. “The intent of this is to get a better picture of what the business case for the greenhouse looks like – the price for the greenhouse and the payback period.”
Farmer profits are boosted by making the best use of the greenhouse space, and researchers hope that architectural software can help. Software will be used to model an optimal configuration for planters in the DWGs. “If you have a high-value product, you want to learn how to maximize the growing space and sunlight to grow as much of it as you can,” Schweser said.
Do it yourself
The point of all this research is a practical one: to empower farmers to adopt the technology. To that end, in 2018 RSDP published a free DIY manual for starting a DWG operation on a budget. The manual breaks down design components, their purpose, construction options and trade-offs. “The DIY manual looks at how someone who is building one of these can fiddle with details to make a lower-cost greenhouse,” Schweser said.
As additional information becomes available from the research, those interested can keep up to date on RSDP’s DWG resource page or by joining the Deep Winter Producers Association Facebook group. Early findings are promising, but research takes time. “We need a nice long set of data points across light intensity, exterior temperature, temperature in the growing area and rock bed, and then to be able to overlap all of these datasets,” Handeen said.
Ultimately, the research has the potential to affect the quality of life of not just individual farmers, but entire communities. “We’re an inspired bunch at RSDP – we think big,” said RSDP Statewide Director Kathy Draeger. “DWGs have touched on something important. We have farmers and researchers all together, trading ideas, on the Facebook page. We’ve gotten calls on this from other countries. The RSDPs’ research and development supports an innovative cold-climate food production system that challenges traditional thinking about how, where and when food is grown. Who’s to say the change we might see with these?”
Handeen agrees. “I really look forward to seeing how they evolve,” he said. “I’d love to see more and more people being able to construct these to the point where they’re like you’re neighborhood convenience store or gas station, where they’re across the landscape in such a density that you can walk to your neighborhood DWG.”
Funders and partners in RSDP’s DWG work include the College of Design Center for Sustainable Building Research; Sustainable Farming Association; University of Minnesota Institute on the Environment; MnDRIVE; Minnesota Department of Agriculture; University of Minnesota Solar Energy Laboratory; USDA SARE; AgCountry Farm Credit Services; AgriBank; Compeer Financial; BFG Supply; Mattson, Macdonald, Young Structural Engineers; and DWG pioneers Carol Ford and Chuck Waibel.