How to eat, drink and keep cool

Rooftop Gardens
My favourite street in Toronto is not much wider than a laneway and is only 75 metres long. It’s lined with turn-of-the-century workmen’s cottages, some old trees, a couple of townhouses, and lush, overflowing gardens.


It’s Bowman St., in the heart of Cabbagetown, running north from Carlton St.  And right at the top, on the other side of Sackville Place, which caps Bowman like the crossbar on a « T’’, is the house where Monica Kuhn lives. Her partner, David Shephard, is the fourth generation of his family to live in the house.


Kuhn is an architect, an exponent of permaculture, and an avid promoter of rooftop gardens. The house that she and Shephard share was built in 1912 and sits on a tiny lot 4.6 metres wide by 12.5 metres deep.


The front yard is not much more than I could lie down in — the front wall of the house, which is just 3.8 metres wide, is only three quarters of a metre from the public sidewalk. But there’s enough room for a grapevine. Five years ago, Shephard planted Concord grapes and now vines cover most of the first-floor wall and are beginning to fill in the second floor. Last year they harvested more than 100 litres of grapes.


It shows, she says, how permaculture works. Permaculture is a philosophy of sustainability developed by Australian Bill Mollison in the late 1970s. Its dominant theme is that everything you do should have more than one purpose.


So, the grapevines not only provide food, they cool the house, provide habitat for birds and insects, add beauty, and protect the wall of the house. Mollison’s theories are laid out in Introduction to Permaculture, published by Tagari Publications of Tyalgum, Australia, and available from Acres, U.S.A., telephone 1-800-355-5313, for $20 (U.S.) plus postage.


I visited Kuhn on a blistering day, with no clouds and a temperature of 30° Celsius. Under the vines, the brick wall, facing south, was cool to the touch.


As Kuhn explains, the brick wall becomes cool overnight and shading by the grape leaves helps the wall retain its night-time coolness. But the grape leaves do more than this to cool the house. They also create a miniature breeze that picks up moisture from the wall and carries it away. Since moisture conveys heat, this increases the insulating capability of the wall..


Here’s how it works. Warm air is drawn in at the bottom of the vines and rises, becoming cooler as it moves up the face of the house. At the top, the cooled air spills over the top of the vines and sinks to the ground, warming as it goes. At the bottom, the process starts over again, thus creating a constant current of air.


And that’s not all. When it rains, the leaves also keep water away from the wall, and that helps protect the wall from deterioration from rain as well as sun.


On the roof, which is flat, Kuhn and Shephard have built a deck where they’ve placed containers growing lettuce, spinach, tomatoes, garlic, beans, eggplants, cilantro, parsley, and a variety of herbs.


« One of my dreams,’’ says Kuhn, « is to see a lot of commercial and industrial buildings growing food on their roofs. Right now, roofs are just so much wasted space.’’


She and Shephard are founding members of Rooftop Gardens Resource Group which is dedicated to « creating a rooftop gardening culture in Metro Toronto.’’ And she and two others have founded a Permaculture Community Action Network which sponsors workshops on permaculture. The network’s e-mail address is


When I turn to Mollison’s book, I see he describes permaculture as: « a philosophy of working with rather than against nature; of protracted and thoughtful observation rather than protracted and thoughtless labour; and of looking at plants and animals in all their functions, rather than treating elements as a single-product system.’’


As Kuhn and Shephard are proving, it’s a philosophy that can work even in teeming downtown Toronto.

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