How to Keep Unwanted Pests Out of Your Compost

Having a compost bin or pile is a great way to have a sustainable garden because it helps you cut back on food waste, and after a few months, you have usable compost to enrich your garden soil. However, a compost bin can occasionally attract unwanted insects and wildlife pests like cockroaches, spiders, and houseflies, or rodents like mice or rats.

If you already have pests, you may decide you want to start over by cleaning out the bin and using some more effective composting practices. These tips can be used to prevent or remove a variety of pests that might be attracted to your compost area. Below, we spoke to a gardening expert about their best tips for deterring pests in compost.

Avoid Composting Items that Attract Pests

Certain food waste items should always be kept out of the compost bin. This includes meat and dairy products, including bones. It’s highly recommended that meat, dairy products, and oils be kept out of the compost because they’re likely to attract pests, especially in the summer months.

Flies, bees, and other insects are attracted to protein foods like these. In hot weather, the decomposition process of these foods may cause unpleasant odors, also attracting pests or wildlife such as carrion birds. Additionally, avoid adding animal feces or cat litter to your compost as these can attract potentially harmful parasites.

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Turn and Aerate

Deborah Niemann, a gardener, homesteader, and creator of the Thrifty Homesteader, emphasizes the importance of turning the compost pile so that the food scraps are buried, as this can help deter bugs like flies.

Use a pitchfork, rake, or another tool (or your gloved hands) to turn your compost layers over will help aerate the materials. Simply pick up the top layer a few inches at a time and turn it over so the underside is on top. Larger food items (like corn cobs) that may draw animals can be broken into smaller pieces to decompose faster.

Maintain Healthy Moisture Levels

Ideally, you want your compost to be moist but not soggy. Adding water every few days helps the decomposition process along. If heavy rains are forecast, you may want to cover the pile or bin to keep it from getting too wet. Too much moisture may encourage fungi which will attract a whole new set of insect pests (not all of them desirable).

Sprinkle Diatomaceous Earth

This natural substance is made of insect exoskeletons and when it breaks down into small particles, the sharp edges effectively kill hard-shelled insects like beetles, fleas, and certain flies. It won’t harm soft-bodied insects like worms or grubs, which are usually considered a boon to the compost pile. Sprinkle it over the top layer of compost every few inches to help deter maggots forming from fly larvae.

Line Compost Bin With Landscape Fabric

If you find that pests enter your compost area from beneath or through cracks in the bin, you can try using a cloth or perforated plastic liner (landscaping fabric can work), leaving the top uncovered for aeration and moisture. This will help prevent wildlife from entering from the lower part of the bin or enclosure.

Niemann recommends having a bin instead of an open compost pile, as this can help keep out rodents, especially if you are adding food scraps to the compost

Try Cayenne Pepper or Essential Oils

Some pests are deterred by certain smells or substances, including cayenne pepper, or strong-smelling essential oils like cedarwood, eucalyptus, or lemongrass. Mice and other rodents dislike peppermint, so this is one to use to try and keep them away. Growing peppermint plants in containers will also help deter mice from entering your compost pile if you locate the containers nearby.

Layer Food Scraps With Plant Materials

When you add food scraps (such as fruit and vegetable peelings) to your compost, adding a layer of plant material over the top is an effective way to keep pests from smelling or accessing the food waste. Place food scraps in the center of the bin, then layer plant material on top. You can also use leaves, grass clippings, soil, or wood chips as the covering layer.