Building a compost bin on your property has two benefits. First, it gives you a source of rich nutrition for your garden and flower beds. Second, it uses nature to recycle.

But compost bins can attract pests — everything from maggots to mice. In fact, a compost pile literally crawls with life. Some of that is inevitable; the challenge is managing maggots and other pests in your compost bin.

If that thought gives you a case of the willies, Dr. Michael Merchant, an entomologist for the Texas A&M Extension Service, says it’s all part of nature. “Compost attracts insects. They help break down the organic material.”

Maggot Magnet

Maggot-infested compost bin.
If your mix is out of balance, an abundance of maggots will appear to take care of the issue. Credit: Tony Alter, CC by 2.0.

Composting speeds up nature’s process of converting organic matter into rich soil. Spiders, beetles, and worms do the early work by breaking down the contents into small pieces that micro-organisms can digest. But a bin that’s not properly managed can draw creatures you don’t want and become a health hazard.

While everything organic will decompose in time, Dr. Merchant advises you to keep certain things out of your bin to avoid unwanted guests. “Food waste can be an issue,” he said.

Most vegetable matter and everything from coffee grounds to eggshells and shredded paper is fine. But meat scraps, bones, and dairy products are a magnet to mice, flies, and other undesirables. Pet waste will do the same thing. Keep them out of your bin. It’s a good idea to bury nonmeat food waste down in the pile to discourage vermin from sniffing it out.

Common Pests

Hairy earwigs.
Hairy earwigs are common in Dallas compost bins. Credit: Bernard Dupont, CC by SA 2.0.

In the Dallas area, compost piles attract certain pests. “Earwigs and pillbugs will sometimes show up,” Dr. Merchant said. Earwigs on your property can damage fruits and garden vegetables. Pillbugs — they’re actually crustaceans rather than insects — are those little creatures we call roly-polies. They eat decaying meat and excrement but will also stick around to munch on just about anything you put in a vegetable garden.

Compost Control

Dr. Michael Merchant
Dr. Michael Merchant

Dr. Merchant says proper bin management is necessary to keep unwanted pests out. The key to that management is heat. “If the compost is active and hot, it’s going to kill most of the pests.” Hot compost piles reach temperatures between 100 and 160 degrees. In addition to killing pests and discouraging flies, the heat will also kill weed seeds and plant diseases in the vegetation content.

A compost bin can be a simple pile of material on the ground, an area enclosed by wood or wire mesh, or a commercially manufactured bin. The ideal location is a spot that gets both sun and shade, away from the house and outbuildings. Build it in layers starting with coarse materials like branches and twigs followed by leaves, grass clippings, and meatless kitchen scraps. Then add a thin layer of soil or livestock manure that’s available at garden centers. Repeat the process until your pile settles in at about five feet high.

How quickly the pile goes from waste to rich soil depends on the time of year and how much work you’re willing to put into it. It converts faster in warm weather.

Your pile should be kept moist, but not soggy. It also needs air, which means turning it with a garden fork (this is the work part). Turn it weekly in warm weather and monthly in winter. If it doesn’t get enough air, it will begin to stink like rotten eggs and draw pests. Following this management plan will give you rich soil within 90 to 120 days, depending on the weather.

Dr. Merchant advises against including any yard waste that might have spider mites. These tiny mites are almost invisible, but you can spot them by the silky webs they deposit on leaves and twigs. Merchant says the mites will survive the composting process and make their way back to your plants. Get rid of infested waste.

He also warns about another pest you definitely do not want in your yard.

Fire Ants

Fire ant pile
Fire ant pile. LawnStarter file photo.

“Fire ants will sometimes build their nests at the outer edges of compost piles.” Fire ants have a vicious sting and can do ugly damage to a lawn. If you spot their mounds around your compost bin, get rid of them with a pesticide made to kill fire ants. Boiling water can also kill them, but because they tunnel so deeply into the ground, it’s hard to get the water to the queens, which is necessary to rout the colony.

Composting can be a rewarding exercise in gardening — or an infested heap — depending on the time and effort you’re willing to spend.