Are there pests in your neighbourhood? You may not even be aware of any small critters like raccoons, mice, rats, insects, etc., until you start to compost. Previously unnoticed pests may now be looking for a new source of food or a cozy bed in your compost pile. The best solution is prevention. If you compost correctly, your pile will be less attractive to pests. This factsheet outlines some general tips and specific methods of protecting your compost pile. Note: Composting will not encourage pest populations to move into your area, though a neglected pile may attract local populations and make them more visible to you.

Prevention tips

• Do not compost any meats, fish, bones, oils, fatty foods or pet manures. Animals may be attracted by the smell and the decomposition process slows down as these materials take longer to break down.

• Place materials that are high in carbon (e.g. dry leaves or dead plants) at the bottom of the pile and along the inside walls of your compost bin. This will provide good airflow, drainage and odour control. Ensure that each layer remains slightly damp to discourage nesting. A well maintained bin will not attract as many pests.

• Cover any exposed food with a layer of dry leaves or a 2.5-centimetre (1-inch) layer of soil or finished compost or bury food waste into the centre of the pile. This reduces smells which may attract pests. Micro-organisms present in the soil help to speed up the composting process.

• Turn or poke holes in the pile every week or two. A regularly "disturbed" pile helps deter pests.

• Take measures to build a "hot" compost pile. This is an active compost pile in which the internal temperatures become very hot. Maintaining a "hot" pile takes some extra effort, but it is an effective way to ward off unwanted pests and you'll have finished compost in a shorter period of time. (See the Building a Hot Compost Pile factsheet for more details.)

• Harvest finished compost at the bottom of the bin every three to six months. This will discourage pests from nesting in the warm finished compost.

• If possible, choose a location for your compost bin that has good drainage and at least partial sunlight. This improves the efficiency of your pile. Place your bin at least 20 to 30 cm (8 to 12 in) from fences, decks and buildings to discourage pests and to improve air flow.

Pests will be less likely to discover your compost if they are not already attracted by other sources. It's a good idea to put your plastic garbage bags into a container at the curb, or to not put out your garbage bags until the morning of collection. Keep leaves and other materials for your pile in a secure garbage can near the composter. Piles of yard waste can provide a safe, warm place for pests to hide or nest. Food waste to be added to the compost pile should be kept in a sealed container away from the bin. Note: Sources of fresh water and bird seed also attract some pests.

Insects
Flies, wasps, hornets and bees can be discouraged from invading your compost bin by covering any exposed food, with a 2.5-cm (1-in) layer of soil or by burying fresh food into the pile. Add air to your compost pile by turning it or create air channels by plunging a broomstick handle into the pile. Keep the pile slightly damp so that it will heat up. Higher temperatures and moisture will kill any fly larvae and discourage bees, wasps and hornets from nesting. If a nest has already been set up in your bin, soak the pile completely with a hose and spray nozzle and leave it damp until the colony vacates the pile. The pile can also be dismantled after freeze-up in the fall.

Rodents and other small animals
Pest-proofing your bin, as described below, will prevent any animal from tunneling up through the bottom, climbing into the bin from the sides or top, or chewing holes in the bin.

• Use hardware cloth to line the bottom and outside walls of your bin. For mice, 0.5 cm (1/4 in), 16 gauge should be used; 1 cm (1/2 in), 20 gauge for keeping out larger pests. (Hardware cloth is galvanized wire mesh, available at most home improvement/hardware stores. Chicken wire is not a good protection against unwanted visitors.)

• Get a tight-fitting lid or modify your existing lid by adding hinges and a latch. Or stretch a bungy cord or chain across the lid and fasten it to the sides of the bin. A heavy brick or rock will also keep the lid secure. Note: Bungy cords can be dangerous if children are assisting in the maintenance of the composter.

• Pile rocks or bricks around the outside bottom edge of your bin as a good temporary measure against some burrowing animals.

Animal repellents

• Environmentally safe animal repellents can be found in hardware and gardening stores or pest control companies.

• For information on ultrasonic sound devices used to repel rodents and other wildlife, contact Health Canada, Pest Management at 1-800-267-6315. You can also ask about the effectiveness of a product you own or want to purchase, and get recommendations.

Other agencies
If rodent problems persist, or in the unlikely event that rodents are nesting in your bin, call the local public health division or an authorized pest control company. If a small animal gets trapped in your bin, call an animal control company or the Humane Society.

Don't give up!
There are many ways to compost. You will need to find the method that works best for you. If outdoor composting proves too difficult, try composting indoors with worms. It's easy and produces great compost.