Composting is an excellent way for gardeners and homeowners to manage organic waste and create nutrient-rich soil amendments. This process of decomposition, however, can inadvertently create a warm, food-filled haven that attracts various unwelcome animals, including rodents, raccoons, and opossums. Keeping these pests out requires a multi-layered approach that secures the composting vessel, manages the materials placed inside, and strategically uses the surrounding environment. Implementing preventative measures helps maintain a healthy compost pile without providing an easy meal for local wildlife.
Structural Solutions for Physical Exclusion
The most effective defense against animal intrusion is a physical barrier. Closed systems like tumblers or sturdy plastic bins with secure lids are superior to open piles for excluding animals. Use containers made from thick-walled material that animals cannot easily chew through or overturn.
For structures placed directly on the ground, install a barrier underneath to prevent burrowing animals. The most effective material is heavy-duty galvanized hardware cloth (18- to 22-gauge), a woven wire mesh. Mesh openings must be no larger than one-quarter inch (1/4 inch) to exclude small rodents, as thinner chicken wire is easily compromised.
Secure this mesh to the bottom of the bin or bury it beneath the perimeter. Cover any vents or openings with the same fine-mesh hardware cloth. Since the lid mechanism is a frequent point of failure, use a tight-fitting lid with a secure latch or place a heavy object on top to prevent lifting.
Managing Ingredients to Reduce Attraction
The materials added to the compost directly influence its attractiveness to animals, as strong odors signal an easy meal. To eliminate powerful scent signals, strictly avoid high-attraction items in backyard composting.
Avoiding High-Attraction Scraps
These items include:
- Meat, bones, and fish.
- Dairy products, fats, and cooking oils.
- Heavily processed baked goods.
These specific materials contain high amounts of protein and fat, which decompose slowly and emit strong, putrid odors that lure scavengers. Focus the compost on plant-based materials, and bury fresh fruit and vegetable remnants immediately and deeply into the center of the pile.
Balancing Carbon and Nitrogen
The ratio of carbon-rich “browns” (like dried leaves, wood shavings, and shredded paper) to nitrogen-rich “greens” (like food scraps and grass clippings) is important. Maintaining a proper balance (approximately 25 to 30 parts carbon to one part nitrogen) helps the pile heat up and decompose faster. A fast-decomposing, hot pile produces less odor and is less inviting to animals.
Regular aeration by turning the compost is also a method of reducing attraction. Turning the pile introduces oxygen, promoting aerobic decomposition, which produces minimal odor compared to the foul smells of anaerobic decomposition. This practice also disrupts potential nesting sites, discouraging rodents from taking up residence.
Environmental Deterrents and Strategic Placement
Securing the bin and managing the contents should be complemented by controlling the environment immediately surrounding the compost area. Strategic placement of the bin is necessary, avoiding areas that provide easy access or cover for animals. Position the composter away from fences, sheds, woodpiles, or dense brush.
Keeping the area surrounding the bin clean is also important. Immediately clean up dropped food scraps or spilled contents. These stray pieces of food can become an initial attractant, signaling to passing animals that a food source is nearby.
Sensory deterrents can be applied externally to make the area undesirable without affecting the compost itself. Motion-activated devices, such as sprinklers or bright lights, create a sudden, disturbing stimulus that discourages nocturnal visitors. These non-lethal interventions teach animals to avoid the area.
Alternatively, strong scents that are unpleasant to animals can be used around the base of the bin. Applying substances like cayenne pepper, strong peppermint oil, or a vinegar solution to the outer walls and ground perimeter deters animals with sensitive noses. These topical deterrents must be reapplied frequently, especially after rain.