Hey, we’re Canadian, right? We’re not afraid of a little cold weather, especially here in the winter sunshine capital of Canada. Sure, lows in the minus 30s and even 40s are common, but that shouldn’t stop a truly intrepid gardener.
When Leo Hunnakko read that Northwestern Ontario receives 340 hours of sunshine in December, January and February, he wondered why there weren’t solar collectors all around the area. He started to research the design of cold climate, year-round solar thermal greenhouses, and found very few resources. He decided to undertake a feasibility study to see if it was possible to operate a year-round greenhouse using only supplementary heat and minimal electrical consumption.
Leo developed a solar greenhouse design, in consultation with various experts and with funding from the National Research Council and the Northern Ontario Heritage Fund. The prototype of the year-round greenhouse, aptly named “GH365,” was built in the summer and fall of 2009 on property in Nolalu, Ontario, that his family homesteaded in the 1930s.
He plants various crops throughout the winter (greens, radishes, onions, broccoli, tomatoes and peppers). One morning, he was planting in the greenhouse while the outdoor temperature was –34OC.
Leo considers himself an organic gardener, and draws inspiration from the self sufficiency of his parents’ generation. He remembers that his family stored root vegetables and preserves made from gathered fruit in a root cellar, and relied on a vegetable garden in the summer. They kept milking cows, and chickens. His father hunted for moose and deer, while he and his brothers caught speckled trout in a nearby creek. Leo sees his greenhouse as a way of returning to this tradition of self reliance.
The 18 by 22 foot (5.5 by 6.7 m) structure has a series of solar water heaters on the roof that heat liquid which then runs through a hot water tank. Hot liquid is circulated through tubes in the floor, root zones and the north wall, which is filled with sand. Thermostats regulate circulating pumps and the water tank has an electric back-up that will kick in after several overcast days, or on excessively cold nights. He has also installed a couple of baseboard heaters (just in case) and a large commercial fan for ventilation.
Leo has been impressed by last winter’s tomato crop, but notes that cold-sensitive crops require careful maintenance of temperature range. It is a balancing act to do this and keep electrical consumption low. In March, the GH365 used 168 kWh of power, at a cost of $20.16.
The building is well insulated, and the south-facing wall, angled at 36 degrees, is glazed with argon-filled double pane glass windows, purchased second-hand from a commercial greenhouse operator. Thermal blinds are used to keep the heat in on long winter nights. Leo is already designing a second version, and would eventually like to see his greenhouse used in First Nations and other rural and remote communities to improve their local food security. But in the mean time, there’s spring salsa to be made!
You can see pictures of the greenhouse and the construction process at Leo’s website at www.greenhouse365.ca.Gwen O’Reilly had to tear down her beloved greenhouse this year to make way for house renovations, but serendipity (and a food security conference) brought her to workshops presented by Leo Hunnakka, and Carol Ford and Chuck Waibel. She hopes to start digging the new foundation by fall, and thinks her writing may suffer when she has her own “Door into summer.”
Photos courtesy of Leo Hunnakko.