Millipedes

• WHAT YOU SEE

A cluster of small, dark, slow-moving bugs with a lot of legs, usually along the foundation or on the driveway after a heavy rain. They curl into a tight spiral when you touch them rather than running. Most people find a handful at a time, sometimes more after a wet stretch, almost always outside or just inside a door.

• WHAT WE SEE

Millipedes eat decaying plant matter, so a cluster of them is really a sign of what's right next to your foundation: mulch that's too deep, a pile of leaves against the house, a woodpile that never dries out. They don't damage the structure and they don't bite, but heavy rain floods them out of the mulch bed and the nearest dry doorway is often the one into your house. A gap under a door or a hairline crack in the slab is usually the specific spot where they cross over. Finding them inside almost always means finding the wet mulch bed outside first.

• HOW WE FIX IT

The quarterly perimeter barrier, three feet up and three feet out, handles millipedes at the same line it handles everything else that's trying to cross the foundation. We'll point out the mulch or debris that's feeding the population, since pulling mulch back six inches from the siding does more than any treatment alone. Door sweeps and sealing a slab crack close off the specific spot they're using to get in. Indoors, cleanup is simple, since they don't survive long away from moisture.

• WHEN THEY SHOW UP

Millipedes show up most in spring and after any heavy summer rain, when their mulch and soil habitat floods. They're rarely a winter problem, since cold weather sends them deeper into the soil. The foundation is where the population lives; a millipede indoors almost always crossed in from there rather than coming from somewhere else in the house.

• WHAT THE PROS KNOW

Mulch touching the siding is the single most common thing we fix. A six-inch gap of bare ground or gravel takes away the bridge.