A beginner’s guide to composting

A beginner’s guide to composting

Did you know that nearly 40% of your garbage is compostable? Through composting, not only do you reduce the amount of garbage in our landfills, you help reduce the number of trips to and from the landfill, which means less carbon dioxide emissions.

Nutrient-rich compost is a plant’s best friend because it helps soil retain water and enables micro-organisms to thrive.

Before starting…

Successful composting means understanding the delicate balance of this mini ecosystem.

Compost is made up of 2 types of organic material:

  • Brown, like dead leaves, soil and shredded paper. Rich in carbon, they decompose slowly because they are desiccated.
  • Green, like fruits, vegetables and coffee grounds. High in moisture and nitrogen, they tend to decay and decompose faster.

A certain degree of humidity is necessary for brown material to decompose. Water your compost with care to make sure the green organic material doesn’t spoil.

What can or can’t be composted…

Do compost Do NOT compost
Sawdust Mollusk and crustacean shells
Wood ashes Treated lawn clippings
Egg shells Oils
Fruits and vegetables Cat litter
Grass (ideally dried) Chemically treated organic material (herbicide and pesticide)
Tea and coffee grounds Potato skins
Bread, pasta and rice (without sauce, oil or fat) Fish
Paper (newspaper, paper towels, tea bags, coffee filters, etc.) Milk products
Plants Sauces
Garden waste Meat

Outdoor composting

Several types of composting bins are available on the market. The most basic models look like garbage cans, but with a hatch through which to mix the compost. Rotatable models help to mix the compost more efficiently and evenly.

Find out if your city has a backyard composting program that subsidizes bin purchases.

Putting the bin in an easy-to-access spot will help you develop good composting habits. The location must be well-drained, not in direct sunlight and sheltered from the wind.

Alternate the layers

Be sure to alternate the layers of brown and green organic material in your composting bin.

This ensures a good carbon to nitrogen ratio for optimal decomposition.

Mix. Mix. Mix.

Mixing your compost once or twice a week will help give a much-needed dose of oxygen to the micro-organisms that feed on the organic material.

Humidity is also more evenly distributed after mixing.

Not too dry, not too wet

Controlling the humidity level of your compost is crucial.

Not enough humidity – and the micro-organisms will die, and the entire decomposition process will stop.

Too much humidity – and the compost will exude a foul odour.

What’s the best way to check the humidity? With your hands. Clench some compost and if water drips between your fingers, it’s too wet. If it breaks apart, it’s too dry. Humidity levels are just right when you can make a ball of compost with your hand.

Beware the stench!

When the balance between brown and green organic material and the humidity level are just right, the compost heap should not be foul-smelling.

So, keep an eye (and a nose) on your compost.

When necessary, add soil or dead leaves and mix your compost more often.

Indoor composting

What are my options if I don’t have a yard?

No problem, composting can also be done indoors, year-round.

There are two ways:

  • Worm composting (vermicomposting)
  • Bokashi

Worm composting

This form of composting uses red wriggler worms that feed on your kitchen waste. The equipment required is very basic. Simply buy or make a bin with holes for air flow (a.k.a. vermicompost bin) to which you add soil and shredded newspaper.


Bokashi (meaning fermented organic matter) originated in Japan, where space is limited.

Simply add a few tablespoons of bokashi medium (bran, rice, etc.) between the layers of kitchen waste and empty the liquid that accumulates over time (don’t throw it away, your indoor plants will love it).

The advantage to Bokashi lies in the amount of material you will be able to compost. Almost everything on your plate will do, except:

  • Meat and fish
  • Dairy products
  • Juice
  • Oils and sauces