Canada: What Is the Future of Urban Farming?
Researchers at U of T Scarborough are testing which crops fare best on city roofs
By Don Campbell
University of Toronto Magazine
Sept 28, 2022
Excerpt:
Isaac, who is an expert on plant-soil interactions and sustainable agriculture, says a major challenge is making sure the crops get enough nutrients. Since the typical green-roof substrate is not as nutrient-rich as soil – and dumping loads of fertilizer on the tops of buildings isn’t possible – the team is testing a type of organic fertilizer.
Heat (too much) and moisture (not enough) are also concerns. Most Toronto green roofs are planted with sedum, a durable and drought-tolerant type of succulent that is efficient at storing water and cooling the soil. The researchers are looking at how different species of sedum might help more sensitive plants, such as crops, grow in harsh conditions.
The researchers are currently growing a variety of crops in 400 individual modules – boxes measuring 60 centimetres by 40 centimetres – on the roof of Highland Hall at U of T Scarborough. The goal is to see how certain plants interact with each other – a tried-and-true farming process known as intercropping. For example, planting legumes contributes nitrogen to the soil, which supports the growth of other crops.
It’s possible that one day your local grocery store will be able to grow food on its roof. Or people living in condos and apartments will be able to ascend a few floors to harvest their own fruits, vegetables and herbs, including ones not commonly stocked in stores. “It could give people living in cities an opportunity to grow the types of culturally important foods they can’t easily get,” says Isaac.
