In theory, greenhouses are an excellent idea to reinforce our food autonomy during the winter, when the fields of Quebec are less generous than at the moment. In reality, growing fruits and vegetables in the cold season is often very energy-intensive… Not for farmer Jean-Martin Fortier, who supplies his restaurant in the middle of winter thanks to an eco-responsible greenhouse.
Jean-Martin Fortier, to whom we owe the Ferme des Quatre-Temps and who is also known as the gardener-market gardener, firmly believes in sustainable agriculture. His latest project, Espace Old Mill, is a farm restaurant located in Stanbridge East, in the Eastern Townships. Open since the spring, this business offers local dishes cooked only with local products. And all the vegetables on the menu grow on the estate… even in the middle of winter!
To achieve this without consuming too much energy, the market gardener has designed a somewhat special greenhouse.
A carbon neutral heating system
The sinews of war is heating. The energy requirement is so great that the standard electric current is not powerful enough. Thus, the majority of greenhouses that operate in winter in Quebec must be heated with propane.
We’re lucky at the Old Mill, because we have access to three-phase electricity. [600 volts]. We set up the greenhouse right next to the path, so we can connect to the network. We don’t need fossil fuels.
Jean-Martin Fortier, market gardener
Indeed, the building uses a 100% electric heating device. It is connected to a fan which diffuses hot air through perforated balloons placed on the ground. In this way, the heat remains around the plants more, instead of being lost in the surrounding air.
“So far, it’s nothing too innovative,” says the market gardener, who uses the hot air tube method in several projects. “The best thing about the Old Mill is that I have a greenhouse within a greenhouse! »
Russian doll greenhouses
In his greenhouse, Jean-Martin Fortier has installed two other greenhouses, smaller ones, to cover the vegetable plants and the hot air tubes. In winter, it is enough to heat these compartments and not the entire space, which represents a significant energy saving.
In addition, the principle of a greenhouse is to let in light while trapping heat. Thus, by installing a second layer during the winter, we can double this effect which keeps the vegetables warm.
“During the day, the ground absorbs heat. And in the evening, when we close the membrane, all this heat accumulated in the ground is released and remains contained in the small greenhouse,” says Jean-Martin Fortier. Just adding the small greenhouse increases the internal temperature by 6 or 7°C.
PHOTO CHARLES WILLIAM PELLETIER, THE PRESS
The arches that form the structure of the small greenhouses
Thanks to this addition, Jean-Martin Fortier estimates that he saves about 30% of energy in winter.
In the summer, he completely removes the membrane from the small greenhouse to grow taller plants, such as tomatoes and peas.
Choose your vegetables
It’s not just about greenhouse design; the success of this carbon-neutral winter crop also lies in the choice of vegetables.
On the one hand, because the market gardener must plant low crops so that they can be covered by the small greenhouse. But above all, because he wants to grow cold-resistant vegetables. It heats the greenhouse to just 5°C to save as much energy as possible.
“I don’t want to heat to 18°C at night in winter,” says the market gardener. I don’t think it’s a model suited to Quebec. »
PHOTO ALEX CHABOT, PROVIDED BY THE INSTITUT JARDINIER-MARAÎCHER
In winter, the plastic membrane is closed over the small greenhouse to lock in the heat during the night.
Rather than growing peppers and eggplants, Jean-Martin Fortier focuses on plants that tolerate minimal heat, such as leafy greens and shallots.
All you have to do is adapt the menu according to the seasons, says the market gardener, recalling that it is still possible to have a variety of foods. “I manage to grow about fifteen different vegetables in the greenhouse in winter. Then, with the reserves of root vegetables and cabbage in the cellar, we really manage to cook interesting dishes. »
Jean-Martin Fortier wants to show people that you can eat locally all year round. He therefore invites the restaurant’s customers to visit the greenhouse. Because the objective of the Espace Old Mill is to promote seasonal tables.
“If I can do it in my restaurant, we can all do it at home! »