Canada: With more than 700 green roofs, Toronto is missing an opportunity to grow its own food
One project led by PhD student Adriano Roberto and master’s student Andrew Nichols currently involves 300 hundred modules – boxes measuring 60 centimetres by 40 centimetres – on the roof of Highland Hall and another 100 modules on the roof of the Science Wing.
By Don Campbell
University of Toronto News
Nov 2, 2021
Excerpt:
A group of University of Toronto researchers are looking at ways to convert Toronto’s numerous green roofs into places where people can grow food.
Canada’s largest city has one of the most progressive green roof policies in the world – and was the first city in North America to enact a bylaw making them mandatory for many new buildings.
“Urban agriculture is emerging as a key component in bringing resilience to our food systems,” says Marney Isaac, a professor in the department of physical and environmental sciences at U of T Scarborough who is overseeing the project along with Scott MacIvor, an assistant professor in U of T Scarborough’s department of biological sciences.
“At the same time, new green roofs are popping up across the city, but they aren’t set up to grow food. This project is merging these two trends.”
There are currently more than 700 dotting the city of Toronto, but MacIvor says most are “extensive” green roofs with shallow substrates (a mix of organic material, crushed brick and minerals like sand and shale) with little to no irrigation. They’re also planted almost exclusively with a type of succulent called sedum. The durable and drought tolerant plants are excellent at storing water and growing in harsh environments, but are functionally limited and help only to improve water drainage and cool buildings.
The U of T Scarborough project, by contrast, is looking at ways to test the limits of what’s possible with current green roof technology and approaches.
