Rooftop farms seeking to meet demand for local food

In the U.S. and Canada, there is a growing demand for rooftop farms to meet the need for local food.

Take Lufa Farms, which built the world’s first commercial rooftop greenhouse in Montreal in 2010. The 31,000-square-foot greenhouse sits on top of an office building and boasts rows and rows of hanging vines and trays with tomatoes, cucumbers and peppers, all grown hydroponically with no pesticides, according to a Financial Post article.

The same kind of project can be found in downtown Vancouver, where Alterrus has built a greenhouse on top of a parking garage. There, herbs and salad greens are grown in water using the VertiCrop system consisting of stacked trays that move on a conveyor belt.

Throughout the U.S., there are similar rooftop farms cropping up. In Brooklyn, N.Y., the article says there are at least three commercial rooftop farms operating, with more planned.

The farms have been created in response to the growing demand for local food.

Proponents say these farms could revolutionize the way cities feed themselves, while turning a profit. “This is the way people want to produce food and this is how they want to get their nutrition–locally,” said Christopher Ng, chief executive of Alterrus, in the Post article.

Lufa Farms recently secured $4.5 million in equity financing that will go towards the construction of  two more rooftop greenhouses in Montreal and one in either in Toronto or Boston. Meanwhile, according to the article, Alterrus expects to have a presence in every major North American city within the next five years.

The idea seems to have a built-in customer base that will expand as urbanization grows, say supporters. Because greenhouses are on the roofs of buildings, they'll typically use half the energy normally needed to heat them.

These farms also recirculate the irrigated water, and transportation costs are low due to the urban location.

And by selling its produce directly to customers at specific drop off areas, Lufa Farms, for example, can cut out retailers to maintain higher margins, and guarantee their produce is delivered the same day it’s harvested.

Alterrus has signed deals with three local supermarkets to supply them with up to 200,000 pounds of leafy greens a year.

But rooftop agriculture won't transform the food system, instead it will be one way to source local food as there are limitations with they system, such as finding buildings that can support the weight of a greehouse.