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Allan designs and plants flowering gardens in Montreal, Zone 5 [USDA Zone 4] .

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Entries in quebec farmers (1)


Update on an Urban Rooftop Greenhouse

Image by Lufa Farms

Several months ago, I wrote about the creation of a rooftop greenhouse that was about to open in an industrial park, here in Montreal. The now-functioning prototype is a 31,000 square foot greenhouse on top of an office building. The incentive to build this project arose out of a concern by its founder that it was difficult to find and get fresh produce in Montreal.

…food is often grown far away from where it is eaten. This meant that our food – whether grown in Quebec or in South Africa – would be handled, packaged, shipped, stored, refrigerated and reshipped perhaps dozens of times before it could appear on our dinner plates. And all along the way, it would become less fresh, less nutritious, less tasty, and be exposed to more potential hazards. The obvious truth was that it would be almost impossible to be truly fresh.

Diagram by Lufa Farms

The proposed business model included an expectation that consumers would pay in advance for weekly delivery of food baskets filled with freshly harvested and grown-close-to-home produce. Also anticipated was the participation of local, certified organic, Quebec farmers and nearby hydroponic growers whose output would supplement the baskets.

Image by Lufa Farms

After only six months of operation, and servicing 700 families, the greenhouse production maxed out, as it cannot meet the overwhelming demand that it generated from the local population. With this vote of confidence, Lufa Farms, which owns and operates the greenhouse, recently negotiated a business arrangement with a developer of industrial buildings to include greenhouses on the roofs of newly constructed buildings. Already in the planning stages is a second greenhouse that will be four or five times larger than the first.

The rooftop greenhouse in winter, image by Lufa Farms.

Lufa Farm’s project is newsworthy for several reasons:-

To be suitable for USDA Zone 4b, this structure is stronger than most other rooftop greenhouses, in order to support Montreal's heavy snow loads. It also had to meet very exacting urban building codes.

Unlike typical greenhouses, this site provides multiple climates as some vegetables require warm zones, others cool environments, while still others need microclimates.

To avoid using pesticides, herbicide, and fungicides, Lufa Farms uses other insects, certain naturally occurring bacteria, weed-free growing mediums, and rigid protocols for maintaining a clean, problem-free growing area.

In additional to individual temperature requirements, each type of plant flourishes in its ideal growing medium, with regulated irrigation, specific nutritional needs, and optimal lighting. Ongoing research projects will help further improve growing methods.

Taste preferences and nutritional values determine the selection of food cultivar grown. In partnership with McGill University, Lufa Farms has developed special methods of determining these values to ensure that their produce is superior to food available elsewhere.

Although water is not scarce in most parts of Canada, this facility treats it as a precious commodity. In three out of four seasons, rainwater is captured and re circulated. The reasons are twofold: - First, is to avoid over-burdening the city water supply and second, is to prevent nutrient-rich wastewater from entering the public water system, where it might contribute to high algae development or the overgrowth of other plants.

Farming in the city, and on top of urban structures, saves money, energy, and reduces emissions. The heating system absorbs natural heat from the sun before it supplements with high efficiency heaters. In addition, high tech energy curtains are deployed at night to reduce energy needs. Because Montreal is very cold in winter and humidly hot in summer, a rooftop location on an already climate-controlled building, helps to further reduce the energy consumption and costs of the greenhouse. Furthermore, this operation helps reduce the carbon footprint and time required to deliver fresh produce to consumer as it is located close to residential neighborhoods and fast-moving main roads.