Urban Greening

Growing gardens on the school grounds means increased green space in our city, which brings multiple environmental benefits.

Cooling

Gardens in ”naturalized” school grounds, especially where there are trees, offer shady areas in the heart of the city for teaching or playing, helping to reduce urban heat, a significant environmental problem in most large cities. Urban areas are hotter than surrounding areas due to factors including: vast expanses of asphalt and concrete surfaces that absorb heat; lack of green spaces or vegetative surfaces; heat produced by industry and vehicles; and large buildings that trap daytime heat and prevent cooling at night. This, in turn, can exacerbate environmental and health problems such as increased energy use by air conditioners and heat-related health concerns. In cities like Toronto, every green area counts towards keeping surface temperatures cooler – not just due to shade but also because leafy plants cool the air through transpiration (water evaporation from the leaves).

Stormwater runoff

Toronto, along with many other cities, lacks porous surfaces to absorb rainfall. Much of the city is paved over with concrete, asphalt and other impervious materials that increase stormwater runoff. When there is a heavy rainfall the runoff goes into the lake, taking with it debris, pollutants, and sometimes raw sewage from an overloaded sewer system. The runoff can also mean increased flooding. Green spaces such as those provided by school gardens absorb rainwater and can reduce pollution and flooding.