Composting in Central Toronto


I would like to compost my organic vegetable and fruit waste and sometimes cooked oatmeal in my central Toronto garden.

1. Do garden worms help to break down compost? If so, I would like to have a bin which will allow worms entry from the bottom.
2. Occasionally, we have had a small rat in the garden and I want to keep any rats out of the compost.

I thought perhaps I could compost in an old green bin with small 1/2″ or 1/4″ holes in the sides for air and in the bottom for drainage and to allow worms entry. Would this work for compost? Should I also wrap the green bin bottom and sides with hardware cloth to keep any rats out? Thank you


Thank you for contacting the Toronto Master Gardeners with your inquiry.

There are many benefits to composting from reducing greenhouse gases, improving soil quality and it even helps in controlling erosion on embankments. To us gardeners’ compost is liquid gold. Before you begin your compost pile there are a few things that you must consider:

The composting process takes anywhere from 6months -1 year before the compost is ready to be spread in the garden. Composters require heat, oxygen and water to produce to specific bacteria and fungi that will break down the organic waste.

When you are ready to site your composter make sure to place it in a location that will receive full sun, the heat from the sun will speed up the decomposition process. If this is not possible, a dark plastic tarp over the bin will help in retaining the heat. To speed up the natural decomposition, chop up or shred any material you add to your compost. Remember not to add weeds or diseased plant material to your bin.

Every few days, or after each new addition, mix the pile with a shovel or pitch fork. This will add air to the compost. Make sure to keep the compost moist but not wet.

Along with garden waste you can include kitchen scraps, teabags, coffee grounds, eggshells. Garden waste along with kitchen scraps is your “green layer”, which is rich in nitrogen. On top of this green layer you need to add a “brown” carbon-rich layer. This  layer includes dried leaves, grass clippings, hay, straw and small twigs. Finally, on top of the carbon-rich layer you need to add a layer of soil. The soil layer  contains the bacteria that help the organic material decompose.

Eliminating specific ingredients such as meat, fish, bones dairy products, grease and oil can discourage wildlife from entering you container. Also, covering aeration holes with wire mesh or hardware cloth can prevent rodents from squeezing through.

There are advantages and disadvantages to using recycled garbage cans as compost bins. Some of the advantages are they are inexpensive, easy to move and cans with lids will deter pesky animals. The disadvantage to using your green bin is  that the can is not large enough to contain the optimal amount of organic matter (1 cubic meter) needed to self-insulate and promote rapid decomposition. Also, you will need to mix your compost after each addition, this will be difficult to do in a small bin.

Earthworms are the ultimate composting machines, consuming and digesting organic matter. Wild earthworms live in the top layers of soil and leaf litter. They do not thrive deep in the ground, as some other worm species do. As a result, duplicating the preferred shallow living conditions with a bin that offers lots of surface area instead one with great depth will increase your composting worm population.

In partnership with the City of Toronto, the Toronto Master Gardeners developed a series of Gardening Guides / Fact Sheets on organic gardening topics: Compost for your Organic Garden

gives detailed  instructions on methods of Hot and Cold Composting.

Good Luck with this project.