Composting is the most effective way the average household can reduce their waste. It is a tremendous soil conditioner that can really help your gardens grow.
- Choose a convenient, level, well-drained and sunny area in your yard
- Start with a layer of finished compost or topsoil. This will provide the microorganisms needed to break down the organic material. There is no need for a chemical compost starter or activator
- Alternate layers of dried out "brown" material with moist "green" material. "Greens" (rich in nitrogen), are fresh plant materials such as green grass clippings and fresh kitchen waste. "browns" (rich in carbon), are dry and dead plant materials such as dried leaves, grass, plants and straw. You will need a mixture of both. A working recipe would be 1/3 to 1/2 "greens" to 1/2 to 2/3 "browns" by volume. Add another thin layer of finished compost or topsoil every so often
- The pile should be roughly one cubic metre in volume, approximately 1. 5 metres (3. 5 feet) x 1. 5 metres (3. 5 feet)
Aerate: Make sure your pile/bin gets enough air. This is necessary for the survival of the aerobic bacteria that break down the material without generating odours. This can be achieved by mixing in coarse material like leaves or green twigs to create air voids and periodically turning the pile with a pitchfork, shovel or compost turner. Turning the pile once every week or two should be enough. More frequent turning disrupts the composting process.
Water the pile: The pile should be as wet as a wrung out sponge. When you squeeze a handful, no drops of water should come out, but the compost should form a ball. It is most effective to water when you are adding materials or turning the pile. An undisturbed pile tends to shed water rather than absorb it. Without water, the microorganisms will die and decomposition will slow down or stop.
Too much water will also drown the aerobic bacteria and may cause unpleasant odours. To correct this, turn the mixture so that the excess water will either drain off or evaporate. Dry material can also be added to help absorb the water.
A hot compost pile is good: As the microorganisms consume the organic material, heat is produced as a byproduct. If you have a large enough volume of material with a good mix of brown and green material and adequate aeration and moisture, your compost pile will start to heat up on the inside, reaching temperatures as high as 40 to 45 degrees Celsius. This is how you know your composter is working. Compost thermometers are helpful, not essential.
Find a Composter
Composting can be done in an open pile or in containers. Containers confine the compost pile and make it more manageable and visually attractive. They can also provide weather protection, aid in heat retention and help keep animals out.
Composters of various design and composition (wood, recycled plastic, wire mesh) are available from local hardware stores and garden centres.
Working composters are on display at the John Janzen Backyard Composting Education Centre, located beside Fort Edmonton Park. There is an attendant at the Centre who can answer any questions you might have.
Good materials for composting
- Yard and garden waste (grass clippings, fallen leaves, flower and vegetable waste, small twigs, straw, hay, peat moss)
- Kitchen waste (fruit, vegetable peelings, tea bags, coffee grounds)
- Wood ashes (from a stove or fireplace, not from chemical logs) can be added in thin layers
Do not add these materials
- Meat, fish, or bones
- Fatty or oily foods
- Cheese and dairy products (these attract animals, create odours, and take longer to break down)
- Pet litter (kitty litter, dog feces)
- Weeds with seed heads or persistent roots (quack grass)
- Diseased plants
- Coal ashes
Maintaining your Composter
- Add fresh materials often. Be sure to mix the new materials with at least the layer just below the top
- Turn your pile once every week or so. Water vapour may be visible as you turn it - evidence that heat is being produced. High internal pile temperatures will help destroy weed seeds, pathogens and insect eggs (though it's less risky to simply keep weeds out of the pile). Turning will also refluff the pile and bring materials from the outer part of the pile into the centre to enable more even rates of decomposition
- Monitor the moisture level. Add drier material or water to maintain the proper moisture level
- Remove finished compost. If you add fresh material into the pile from the top, the more finished material will end up at the bottom. Finished compost is dark brown in colour, crumbly, lightweight and has an earthy odour. The origin of some material may still be evident but these will break down further after the compost is dug into the garden
- Break the materials into small pieces before adding them to your pile. Smaller pieces break down quickly. This can be done with pruning shears, scissors, a machete, your lawnmower or a weed eater in a garbage can
- Cover food waste to avoid attracting insects. Bury your kitchen scraps as you add them. In winter months, when flies are not a problem, switch to using leaves as cover material
- Save some leaves from your fall/spring clean-up to add to your compost pile during the summer months when "brown" or carbon rich material is scarce. Dry leaves will add air voids to your composter, especially if most of your other material is grass clippings. The leaves' high carbon content will also offset the excess nitrogen in grass and prevent any odour problems from developing
- Don't compost only grass clippings. Grass clippings alone tend to clump, compress, and hinder aeration. Odours may also be produced as the excess nitrogen in grass is converted to ammonia. An easier choice is using extra clippings as mulch, or simply leave clippings on the lawn. If you have no access to dry carbon materials, dry grass clippings in the sun, and then add them. During periods when grass grows rapidly, some of the clippings can be bagged and added later to avoid overfilling the composter with one kind of material
- Winter composting: Winter weather will stop or drastically slow down the composting process. Keep the pile working longer by siting it in a sunny location to take advantage of solar gain, and shelter it from windchill using bales of hay or bags of leaves, or by tucking cardboard inside the north and west sides. Once your bin is full, kitchen wastes may be put lined containers, left outside to freeze, and added the following spring. If your bin is far from the house, the lined container method may make winter composting more convenient. If using this method, consider how you will carry all that material to your bin in spring and keep in mind that if allowed to sit unfrozen in its container it will develop an unpleasant odour. Once air is mixed in, the odour will become less noticeable - cover with soil if necessary
- Request a Compost Doctor: Waste Management Services has a team of helpful Master Composter Volunteers who are happy to help you with your composting problems. Request a compost doctor at MCRP@edmonton.ca, or by phoning the Master Composter/Recycler Program at 780-496-5051
Second Nature® horticultural compost and blended topsoil products are available for sale at various locations.
Learn the basics of composting and grasscycling at the John Janzen Backyard Compost Education Centre.
For More Information
In Edmonton: 311
Outside Edmonton: 780-442-5311