Urban rooftop gardens: sustainability is looking up

As the interest in living local continues to rise, urban dwellers are looking for a new space to grow food. Enter the rooftop garden.

By keeping food production close to home, rooftop gardens help to reinforce the idea that urban centres have an important role to play in the future of food production and also deconstruct the notion that food is produced in rural settings to be (largely) consumed by denser urban populations.

Benefits abound

Urban rooftop gardens, also known as green roofs, which are located at the top of a house or a building that is protected with a waterproof barrier, are cropping up in cities across North America.

Not only does a green roof have the potential to beautify an often overlooked space and to produce food that the inhabitants of the building can consume, but green roofs can also minimize the effect of rain runoff, such as flooding or even water supply contamination. In fact, the Green Roofs for Healthy Cities (GRHC), an industry association in North America indicates that green roofs can prevent 70 to 90 per cent of the precipitation that that falls on them in summer months from running off.

On top of this, urban gardens filter out pollution, purifying the air, and they keep the roof warmer in the winter and cooler in the summer, which moderates the amount of energy necessary to maintain the temperature indoors.

A green roof for all seasons

Despite the many advantages of rooftop gardening, urban gardeners are often limited by the climate of the city they live in, as this affects how much they can grow and when.

Building rooftop greenhouses, however, can extend the growing season. Lufa Farms, a company based out of Quebec, did just this in 2011, when they built the first commercial rooftop greenhouse in the world. This greenhouse is a sprawling 32,000-sq.-ft. on top of a building in Montreal, and it cultivates veggies like peppers, cucumbers, Boston lettuce and Swiss chard.

Since then, Lufa Farms has added a 43,000-sq.-ft. greenhouse to a rooftop in Laval, where it’s main focus is growing tomatoes.

The more than 200 metric tonnes of produce that Lufa grows every year is used to feed city dwellers. Consumers place orders for Lula Farms produce online and the company harvests to meet demand, a move that keeps waste to a minimum. Currently, Lufa ships around 5,000 baskets of produce to Montreal-based grocery stores and consumers every week.

Unlike produce that is imported from more distant markets, such as California, where it must be picked long before it is ripe to avoid its spoiling en route, Lufa Farms’ produce is picked ripe and taken to the central distribution centre to be sold that day.

Lufa Farms’ successful deployment of this type of distribution model makes it easier to envision a future in which cities are self-sufficient.