Freshpal Farms is believed to be the largest commercial passive solar greenhouses in Alberta. It is located east of Olds in Mountain View County. This greenhouse is 100% powered by the energy of the sun and cultivates vegetables year-round – even during Alberta’s harsh weather. It does not use any conventional fossil fuel sources and relies on no other heat source other than the heat from the sun.
Dong Jianyi, co-owner and operator of Freshpal Farms, arrived in Canada in late 2014. With a background in geology from China, Jianyi made a drastic career change and quit his job at an oil service company to pursue agriculture.
Passive solar greenhouses are common in China and Jianyi was interested in duplicating the same model in Canada. He spent 6 months learning the different models of passive solar greenhouses, while travelling back to the Shan Dong province in northern China, where he talked to farmers, builders, and manufacturers as part of his research.
Freshpal Farms’ greenhouse is over 100 meters long, 10.5 meters wide and 6 meters tall. It runs east to west to maximize exposure to the sun, with a 750 square meter growing area. The roof and south facing wall are made up of two layers of polyolefin plastic, while the north wall is made of clay. This 1-meter thick clay acts as a heat sink, capturing and storing heat from the sun during the day, and releasing it through the night.
“Clay holds the heat,” explains Jianyi. “The sunlight heats the back wall to a very high temperature – about 30 degrees. During the night, the clay releases the heat gradually.”
In early December, tomatoes and cabbages were growing when the outside temperature was -5C. In 2021, Freshpal Farms produced more than 13,000 kilograms of tomatoes alone.
The solar greenhouse is large enough for Jianyi to operate a small tractor. He sows directly into the soil and relies on using compost and manure to enrich the soil, and avoiding the use of pesticides, herbicides, or fungicides.
Jianyi believes that growing in the greenhouse provides greater environmental control and certainty over the outcome of crops. He works closely with educators at Olds College, along with Rural Routes to Climate Solutions, to create learning opportunities for other Albertans interested in the passive solar greenhouse model.
Jianyi’s passive greenhouse at Freshpal Farms has served as a demonstration farm for other farmers to come and learn about the possibility of investing in passive solar technology. In fact, he’s planning on building a second solar greenhouse.