Community gardening is a popular Canadian pastime, but only the Iqaluit Community Greenhouse Society can stake a claim as the most northern society-driven greenhouse above the treeline.
The greenhouse was built in 2007 with partial funding from the government of Nunavut. Constructed of polycarbonate over a steel frame, the greenhouse covers about 90 square metres. From June to September, society members grow and harvest lettuce, spinach, kale, beans, peas, radishes, carrots, cherry tomatoes, peppers and herbs.
“We rely exclusively on solar heat,” says society treasurer Suzanne Etheridge, who moved to Iqaluit from Ontario in 2010. “We also employ passive heating techniques, by filling large garbage cans with water. They heat up during the day and moderate cooler temperatures overnight.”
The greenhouse initially operated with members assigned to specific tasks and crops, but recently switched to a community-oriented approach. The society’s 30 members and volunteers now share work and harvests equally. This year’s harvest has been particularly successful and the society carefully records each detail of its operation to help replicate success in Iqaluit, or in other greenhouses across the territory.
The Cold Climate Innovation (CCI) program of the Yukon Research Centre at Yukon College is also conducting research designed to improve the efficiency of northern greenhouses.
“My favourite fruit is the wild Yukon strawberry, one of the sweetest,” says Stephen Mooney, director of CCI. “But they’re tiny — it’s a labour of love to pick a cupful. If the Yukon wants to enjoy fresh produce all year round and increase food security, only greenhousing can make that happen.”
The centre’s on-campus greenhouse has demonstrated that polycarbonates, which admit and diffuse sunlight from any angle, are superior to glass glazing. A northern greenhouse built with three insulated sides and glazing only on the south face will perform more efficiently than one with glazing all around.
“Much of our work is designed to extend the growing season back from spring and forward into fall,” says Mooney. “However, if you’re going to do a commercial, year-round greenhouse, you’ll need heat and light — and energy is expensive in the North.”
Mooney points to combined heat and power (CHP) plants fueled by natural gas or biomass, such as wood waste, as one possible solution.
“You could provide heat and power to a community, then use excess heat for a greenhouse,” he says. “If you could use the CO2 produced by the engine as fertilizer, it would be a brilliant way to close the loop.”
One of North America’s largest greenhouse tomato growers, British Columbia-based Houweling’s Tomatoes, is doing just that at its operations in Delta and Camarillo, Calif. The grower has installed three GE Jenbacher J-624 natural gas-powered engines in California and has plans to install two in Delta in 2014. In both operations, CO2 is transformed into fertilizer available to plants using a catalytic converter, while excess electricity is sold to the grid.
“In California, greenhouses help us to reduce the variances in the volume of tomatoes we can produce,” says David Bell, chief marketing officer with Houweling’s. “There’s a tremendous demand for greenhouse-grown tomatoes, but if you can’t supply the same volume of product when days are shorter and the intensity of the sun is less, you risk losing market share.”
Although the sale of excess electricity to the grid has made a stronger case for the CHP systems, Bell says they weren’t essential to the company’s economic case for the investment. Houweling’s plans to replicate its success with a CHP-powered greenhouse facility in Anchorage, Alaska. The greenhouse will provide excess heat and electricity to a neighbouring correctional facility that is underserviced for power.
“The key to operating in the North is a large enough market for our product and a customer for excess heat and electricity,” says Bell. “But a ready supply of natural gas is essential to operating a commercial greenhouse economically in the North.”
In an ideal world, Etheridge says she’d like to see construction of a larger greenhouse in Iqaluit, one that could supply the community with fresh produce year-round.
“There are many challenges, including lack of daylight in the winter and almost too much in the summer, lack of suitable soil, and difficulty in producing compost,” she says. “We’re always on the lookout for new funding sources for expansion and new ideas to increase our growing season. For now, I’m happy with what the Iqaluit greenhouse offers — a good community atmosphere, fresh produce, and a place to get my hands a little dirty.”