We get multiple questions every year about the City of Toronto’s free compost provision program, which can be picked up by residents from April through October at Leaf Compost Depots and Community Environment Days.

There is a lot of information provided by the city (we encourage you to read more on the program for more detailed information) and we called in to Toronto’s 311 service to find out some more information to see if this is something you’d want to be using in your vegetable garden, or restricted to your lawn and flower bed.

First, here’s a simplified overview of the program. Yard waste and green bin waste gets picked up by the City and taken to the Disco Organics facility. This can include fall leaves, food scraps, pet waste, dairy products, diapers and more. Here’s a full list of what can and can’t go into the green bin.

After processing the materials get piled in long triangular windrows, often 3-4 meters tall. The compost is monitored and turned to facilitate the decomposition process. It gets stored for one year to continue to cure and ensure the process is completed. This compost is then used for city parks and as part of the compost provision program. Every load the city receives is tested according to Ontario Compost Quality Standards (pdf link)

The city suggests the compost can be used for flower beds, vegetable gardens, trees, and lawns while being mixed with soil at ratio of one part compost to six parts soil. This is the first step where people mistakenly use it straight from the depot without mixing it with other top soil first.

In general, we believe the city’s compost program is great for all types of ornamental gardening – such as lawns, flower beds, trees, and shrubs. Having the compost tested to meet provincial and federal standards provides peace of mind for us to recommend it for most gardening applications. However, due to concerns about levels of heavy metals, and harmful pathogens found in things like cat litter and dog feces, these chemicals/elements may not break down even under high temperature composting. One resource we read mentioned heating the compost to at least 73C to kill off the toxoplasmosis parasite often found in cat feces. As a result, we tend to err on the side of caution and would avoid putting this in our vegetable garden. For us, this is a risk we’d rather not take, especially when we have other sources of excellent compost, such as organic worm castings to be using in the garden.

For more information on the composting program, check out the City of Toronto’s website as well as these documents from on the and the Canadian Council of Ministers of the Environment’s Guidelines for Compost Quality (pdf link)

Cover Image by Jamie McCaffrey, used under its Creative Commons license.

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