Why Do I Keep Finding Millipedes In My House?

Summer brings all kinds of seasonal surprises. Some are great—like spur-of-the-moment trips to the beach and invites to a new friend’s backyard pool. Others are not so great—like week-long heat advisories and unwelcome house guests in the form of creepy, crawly millipedes.

When the weather takes a turn in late spring or summer, we unwillingly welcome the basement’s seasonal tenant—an infestation of millipedes that seem to scatter all over with no rhyme, reason, or identifiable inlet. If you’ve experienced this phenomenon, here’s your guide to understanding where the millipedes come from, what brings them into your home, and how to keep them out.

What Are Millipedes?

Millipedes are common arthropods that have two pairs of jointed legs on most body segments. For the most part, they’re slow-moving detritivores, which means they feed on decaying leaves and other dead plant matter. Millipedes generally live underground in damp and dark places. Around your home, they’re drawn to dead leaf piles, mulch, flower beds, and rocks. In small numbers, they can be helpful to gardens as they break down organic material that will fertilize plants. But in large numbers, they can be detrimental because they may eat the roots, stems, and leaves of living plants due to an absence of sufficient dead material.

Do Millipedes Sting Or Bite?

Millipedes don’t bite or sting and are generally harmless to humans. However, don't confuse a millipede with centipedes, which have a painful, venomous bite. You can tell the difference by the number of legs, as centipedes have just one set of legs per segment instead of two. Centipedes also tend to have longer legs and run faster.

Though millipedes don't bite, it's best not to touch them or pick them up. Millipedes have defensive glands that emit a foul-smelling fluid when disturbed or handled. The secretions can irritate your skin and mucous membranes.

What Brings Millipedes Inside?

Millipedes are attracted to cool, damp places, so when summer heat makes the conditions outside too hot and dry, millipedes often migrate inside in search of more favorable living conditions. In addition, if it becomes too wet outside due to heavy summer rain, they’ll also seek shelter indoors. Basements, crawl spaces, and overcrowded garages (where it’s often cool, dark, and damp) are especially vulnerable to millipede infestations.

How To Get Rid Of Millipedes In the House

There are a few ways to rid your home of millipedes. The first is to simply vacuum them up with a shop vac or other vacuum. This is easier to do than it sounds, because millipedes typically curl up and die after a few days in the dry interior of a home.

You can also buy liquid insecticides or insecticide granules to spray or sprinkle around your home’s foundation and exterior walls and help deter insects from coming indoors. Pay special attention to doors, windows, and other possible entry points where millipedes could be entering your home. Natural deterrents like essential oils and cayenne pepper can also be sprinkled or sprayed around problem areas.

How To Stop Millipedes From Coming Into Your House

Once you’ve successfully rid your home of millipedes, there are several steps you can take to keep them from coming back:

1. First, inspect the foundation and crawl spaces of your home and remove anything that could cause a build-up of moisture and provide hiding spaces. This could include dead plants, piles of leaves, stones, or other debris. Pull mulch 6 inches away from the foundation in problem areas.
2. Second, check for water that’s not draining properly. Are there frequently pools of water collecting around your home’s foundation? They could be attracting millipedes. The same goes for leaky pipes or faucets inside your home. Repair any leaks and install splash guards, drains, or pipes to keep water from collecting around the foundation.
3. Finally, look for any gaps, cracks, or openings in doors and windows that enter your house and have them both caulked and sealed to keep unwanted pests outside. Also, seal any cracks in foundation walls or at the bottom of your basement walls.