Setting up a compost bin in a yard or on a balcony is an accessible project that does not require complex equipment. Most Canadian households have enough space to compost, and several municipalities offer subsidized or free bins to residents.
Choosing the location and container
An outdoor compost bin is ideally placed in partial shade, directly on the ground. Contact with the soil gives worms and microorganisms access and speeds decomposition. A spot that is too sunny dries out the pile, while full shade slows biological activity.
For a household of two to four people, a container of 200 to 400 litres is usually sufficient. Enclosed bins with lids help limit access by wildlife — raccoons and skunks are common in many Canadian urban areas.
A home compost bin with materials decomposing. Source: Wikimedia Commons (CC BY-SA 4.0)
The green and brown ratio
The key to odour-free compost is balance between nitrogen-rich (green) and carbon-rich (brown) materials. A rough ratio of one part green to two parts brown is a good starting point.
Green materials to add
- Vegetable and fruit peels
- Coffee grounds and unbleached paper filters
- Tea bags (without metal staples)
- Fresh grass clippings
- Uncooked vegetable food scraps
- Spent flowers
Brown materials to add
- Dead leaves (abundant in autumn in Ontario and Québec)
- Unprinted corrugated cardboard, torn into small pieces
- Newsprint (without glossy inks)
- Straw or hay
- Untreated wood chips
- Eggshells (also contribute calcium)
Good to know: Oak and maple leaves are common in Canada's wooded regions. They break down more slowly because of their tannin content. Shredding them before adding them to the bin speeds decomposition.
Materials not to compost
Some materials can attract pests, create odours, or introduce pathogens into the compost:
- Meat, fish, and seafood
- Dairy products and cheese
- Cooking oils and fats
- Large amounts of bread and pasta
- Diseased plants (mildew, powdery mildew)
- Pet waste
- Treated or painted wood
Compost bin installed in a garden. Source: Wikimedia Commons
Maintenance and monitoring
An active compost pile needs little intervention, but a few regular steps optimize the process:
Aeration
Turning the pile every two to four weeks with a fork or compost aerator supplies oxygen for aerobic bacteria. An unturned pile can become anaerobic and develop sulphur odours.
Moisture
The pile should stay as damp as a lightly squeezed sponge. In summer in dry regions such as the Prairies, light watering may be needed. If the pile is too wet after heavy rain on the West Coast, add dry brown materials to absorb excess water.
Particle size
Breaking materials into smaller pieces before adding them — especially branches and peels — reduces decomposition time. A chipper can help with large amounts of woody material.
When is compost ready?
Mature compost has three distinct traits: dark brown to black colour, an earthy forest smell (no unpleasant odour), and a crumbly, uniform texture. The time required ranges from three months in summer (with frequent turning) to eighteen months for compost left without intervention.
A two-bin method — one filling, one maturing — keeps finished compost available at all times.
Using finished compost
Mature compost can be worked into vegetable garden soil (5 to 10 cm mixed into the top 20 cm), used as mulch around fruit trees, or used to improve clay or sandy soil structure. In large cities such as Montréal and Toronto, several community gardens also accept donations of home-produced compost.
External references
For local regulations and bin distribution programs, see: