Composting is a system of managing natural process of decay and replenishment in the soil for the benefit of your garden.
It’s nature’s way of recycling and returning organic matter to the earth. Compost contains valuable nutrients and micro-organisms to improve the soil. It’s the building block of an ecological approach to gardening and is easy to start and maintain.
What is Compost?
Compost is not soil! It is an organic soil supplement that:
- Slowly releases nutrients
- Increases water retention capacity, and
- Builds healthy soil ecosystems for long term soil health
- Compost is a valuable resource for your lawn and garden
- It’s a good alternative to peat, which takes thousands of years to form and is not renewable
- You can make compost yourself in 3-6 months, and for free
Best uses for compost:
- Mulch beds – Applying 2-3 inches on top of your garden bed will help soil retain moisture, discourage weeds, and provide nutrients.
- Top-dress lawns – Aerate your lawn, then spread a 2″ layer of compost over it.
- Prepare your vegetable garden – Dig in 3-4″ of compost each year.
- Create a growing medium – For patio pots add 2 parts compost to 1 part soil and 1 part vermiculite.
How Composting Works
We expect to see worms, beetles, and wood bugs at work in the compost, breaking down the material. The bulk of the work, however, is done unseen – by bacteria. A compost pile may get as hot as 55 degrees C from bacteria hard at work.
Because bacteria are the most important organisms for efficient composting, we want to create an environment where the bacteria can thrive. This means providing them with the right materials, moisture, content and amount of air.
Earthwise Society periodically offers backyard composting and worm composting workshops. Check our workshop schedule for more info.
How to Compost
The two most important food sources for bacteria are carbon and nitrogen. Carbon sources are usually brown materials like leaves, straw, etc. Nitrogen sources are green materials like fresh grass clippings or fruit and vegetable scraps. Aim for a 50/50 ratio of brown to green materials in your compost.
The key to creating rich compost is to add a variety of material. This will add an array of nutrients to the compost, which one material, such as grass clippings cannot solely provide.
Items to Avoid
|Grass – not treated w/ pesticides||Leaves||Fatty/Greasy foods|
|Plant trimmings (under 2″ chunks)||Fine Sawdust||Cooked foods|
(horse, cow, rabbit, guinea pig)
|Raw Fruit/Vegetable scraps
(under 2″ chunks)
|Twigs and branches –
(2″ chunks or smaller)
|Coffee/Tea (with bags/filters)||Dead plants – dried||Buttercup and morning glory|
|Crushed Egg shells||Spent potting soil||Seed-heads of opportunist plants|
|Weeds without seed head||Hair (not chemically treated)||Kitty litter|
|Weeds in seed|
Building the Pile
To achieve the 50/50 ratio of green and brown materials, it is important to layer in your compost bin. When starting a pile, begin with about a 5-10 cm layer of brown twiggy material. This will help with airflow and drainage at the bottom of the pile. Then add a green layer, followed by a brown layer.
Continue to layer as much as possible: this will help you get the right mix of materials, and stop items such as grass clippings from matting into thick clumps.
The top layer should always be a brown layer, such as leaves or straw. When you add kitchen scraps, pull back the brown layer, and bury the scraps in the middle. The top brown layer will help keep smells down, and burying the kitchen scraps will keep pests away.
TIP: Stockpile your leaves in the fall, saving them until spring and summer when you are producing large quantities of green materials. This way you can layer browns and greens throughout the year.
Like us, bacteria and other organisms in the compost need water to survive. Bacteria also use water films as transportation routes. Too much water however, blocks air flow, and will create odours. The general rule of thumb is to keep the pile as moist as a “wrung out sponge.”
If you find that the compost pile is dry, take a hose or watering can, and add some water. If the compost is too wet and starts to smell, add dry brown materials to soak up excess moisture.
Turning the compost pile adds air and speeds up decomposition. Either aerobic or anaerobic bacteria will work on your compost. Anaerobic bacteria produce methane gas, which smells. Therefore, in our back yards, we want to encourage aerobic bacteria, which need oxygen, but do not produce methane. To do this, air must be allowed to flow through the pile.
The more you turn the pile, using a pitchfork or an aerating tool, the faster the composting process will work. By turning the pile once a week, compost can be ready in as soon as 3 months.
TIP: If you ever have trouble with your compost, either because of smells, or lack of efficiency, the first way to remedy the problem is to aerate.
Backyard composting requires a well designed bin that will the pile confined to a limited area and prevent rodents or other animals from getting into the compost.
Place your bin directly on the ground, on a flat, well-drained area, preferably in sun but shade will do.
Choose a place that’s convenient for you since you want to add materials frequently.