Why do I suddenly have millipedes in my house?

It can be alarming to suddenly find millipedes in your home, seemingly coming from nowhere. Millipedes are arthropods with long, cylindrical bodies made up of many segments. They have two pairs of legs per body segment and are usually 1 to 2 inches long.

While millipedes are harmless, their sudden presence inside a home is often unwanted. So what would cause these many-legged creatures to suddenly invade your living space? There are a few key reasons millipedes may start appearing in a house.

Changing Weather Conditions

Millipedes prefer moist environments and thrive in damp conditions outdoors. When the weather turns wetter, such as during spring rains or increased humidity, millipedes become more active as they search for food and shelter. Your home’s foundation may provide just what they are looking for.

Cracks, crevices, and gaps around windows, doors, pipes, vents, and siding provide entry points for millipedes. Once inside, they will congregate in moist, humid areas like basements and bathrooms. Sudden millipede sightings indoors often correlate with rainy periods that drive them to seek drier shelter.

Disturbances to Their Habitat

Millipedes live in leaf litter, compost piles, mulch beds, and other decomposing plant matter outdoors. When these areas are disrupted, such as during landscaping projects, millipedes go in search of new homes. Raking leaves, removing wood piles, planting new garden beds, etc. can inadvertently send millipedes towards your house.

Likewise, if heavy rains, floods, or droughts alter their typical habitat, they will be compelled to seek more favorable living conditions. Your home’s moist, cool environment is a tempting alternative. Millipedes appearing after habitat disruptions outside indicates they have relocated indoors for safety and resources.

Lack of Predators

Outdoors, millipedes have many natural predators like birds, spiders, centipedes, and small mammals. These predators help keep millipede populations in check. However, once inside your home, millipedes have escaped these threats.

Without predators feasting on millipedes regularly, their numbers can quickly rise. A few millipedes may sneak in at first. But without any reptiles, amphibians, mammals or insects to hunt them inside, millipede populations can rapidly multiply. Soon you have a full-blown millipede infestation on your hands.

Attractive Conditions Indoors

Not only do homes provide safety from predators, but they also offer ideal living conditions for millipedes. They prefer temperatures between 60-80°F with high humidity. Most homes fall squarely within these parameters.

Millipedes also feed on decaying plant matter. They will happily munch on houseplants, leaves and grass blown inside, pet food, lint, paper, cardboard and various household debris. Homes give millipedes ample food sources.

Between desirable temperatures, moisture, food and shelter, it’s no wonder a stray millipede or two would invite all their friends once inside your home. Soon you have a regular millipede hangout spot if you don’t take action to remove them.

Signs of a Millipede Infestation

A few occasional millipede sightings in a home is unsettling but not yet a full-blown infestation. However, once millipedes have made themselves at home in your home, evidence of large numbers will become clear. Watch for these signs of a severe millipede infestation:

Visible Millipede Traffic

Once millipedes establish colonies inside, you will start noticing far more millipedes crawling across floors, walls and ceilings. Seeing 10 or more millipedes daily, particularly in a confined room, signals a substantial population. Numerous millipedes gathering near doors, windows or crawl spaces indicate entry points. Heavy traffic pathways also reveal areas they frequent.

Dead Millipede Bodies

While disconcerting, dead millipede bodies confirm an existing problem but also show treatment methods are working. Millipedes have short life spans averaging 1-2 years. Dead specimens likely succumbed to old age, pest control products or insufficient habitat. Numerous deceased millipedes suggest an infestation was or still is present.

Frass Droppings

Frass refers to insect waste droppings. Millipedes produce small, pellet-like frass. Scattered brown granules along floors, walls and countertops point to sustained millipede activity in an area. High frass concentrations pinpoint colonies in that location. Droppings may stain porous surfaces over time.

Decaying Odor

A distinctive decaying odor emanating from an area of the home could mean millipedes. When crushed or disturbed, millipedes release benzoquinone and other defensive chemicals that produce a foul rotten stench. The smell intensifies with higher populations. A pervasive decaying odor likely indicates a large nearby colony.

Damage to Household Items

Although millipedes don’t directly damage homes or possessions, high activity levels result in collateral damage. Food containers may be chewed through, houseplants eaten, fabrics soiled by frass, and documents or photos stained by secretions. Seeing numerous household items incidentally ruined by millipedes points to rampant infestations.

Where Do Millipedes Hide in a Home?

When millipedes move into a home, they need somewhere to establish nesting colonies. Favorite hiding places include:

Basements and Crawlspaces

Like most insects, millipedes gravitate to basements and crawlspaces. Here they find ideal dark, moist, cool conditions year-round. Basement window wells, floor drains, cracks in the foundation walls, and storage clutter offer attractive harborage. From basement colonies, millipedes can access upper floors through vents, pipes and wiring holes.


Closets contain everything millipedes need. They are warm, humid and dark. Stored clutter like boxes, clothing piles, shoes and bags give millipedes ample hiding spots. Decaying food, dust and fibers provide food sources. Closets nearest外 the basement or first floor exterior walls tend to harbor the most millipedes.

Hollow Furniture Legs

Sofas, chairs, tables, beds and other furniture with hollow legs offer wonderful millipede real estate. Hardly disturbed by humans, hollow furniture legs are ideal secluded spaces for colonies. Clutter stored under furniture also attracts millipedes. Carefully examine undersides and inside hollow legs to uncover hidden colonies.

Firewood Stacks

Firewood neatly stacked inside or near the home provides 5-star accommodations for millipedes. The bark harbors fungi and decay that millipedes eat. Stacked cordwood has gaps and tunnels galore for nesting and hiding. Millipedes lay eggs and thrive in firewood before marching indoors for winter. Store firewood well away from the home.

Leaf Litter and Woody Debris

Leaf litter, mulch, compost, wood chips, sticks, logs and other woody yard waste heaped near the home’s foundation are welcome mats for millipedes. Clean up this organic matter so it doesn’t provide pathways for outdoor millipedes to enter the structure. Removing woody debris eliminates ideal habitats right next to entry points.

Do Millipedes Bite or Sting Humans?

Giant African millipedes and a few tropical species can nip or pinch in self-defense, but most backyard millipedes in North America cannot bite or sting. They do not suck blood or spread diseases to humans. Millipedes have two means of defense:

Curling Into a Spiral

When threatened, millipedes will curl into a tight spiral, hiding their legs and head inside their hard exoskeleton. This protects vulnerable body parts from predators. Curled millipedes may remain in spiral formation for hours until the danger passes. If you try to unroll them, millipedes will secret foul-smelling chemicals.

Releasing Repellent Secretions

The primary way millipedes defend themselves is by releasing noxious secretions to repel predators. Glands along the sides of their bodies produce a variety of chemicals like benzoquinone, hydrogen cyanide, and alkaloids. When threatened, millipedes ooze these smelly, toxic substances to deter attackers. The secretions can stain surfaces and irritate skin.

While millipedes won’t bite or sting, the secretions may cause minor skin irritation in sensitive individuals. Use gloves when handling millipedes and avoid rubbing your eyes afterwards. Make sure to wash your hands thoroughly. For most people, millipedes are not dangerous, just a nuisance.

How to Get Rid of Millipedes in Your House

If millipedes start frequenting your home, implement control tactics quickly before populations escalate. Combining prevention, non-chemical and chemical methods works best to kick millipedes out for good:

Remove Exterior Habitats and Entry Points

Start by making your home’s exterior less welcoming to millipedes. Eliminate leaf litter, firewood, compost and moist woody debris near the foundation that attracts them. Use caulk and sealants to plug cracks, gaps and openings around windows, doors, siding, pipes and wires where millipedes enter. Install door sweeps and weatherstripping to block gaps under doors. Fixing gaps in the home’s exterior removes entryways and desirable habitat.

Install Dehumidifiers

Because millipedes require moisture, drastically drying out your home’s interior helps make it less hospitable. Run dehumidifiers in basements, closets and problem rooms to lower humidity below 50%. Remove potted plants and limit water sources to dry up areas. Improved ventilation also lowers moisture. Less humidity makes it harder for millipedes to thrive inside.

Apply Diatomaceous Earth

Diatomaceous earth (DE) is a natural insecticide made from fossilized algae. The powdery chalk-like substance clings to millipedes, absorbing the protective oils on their cuticles which causes dehydration and death. Apply Food-Grade DE along baseboards, under appliances, inside cabinet recesses, around pipes and other millipede paths. Wear a dust mask when using DE to avoid breathing in the particles. Be sure to apply light dusting coats to allow the DE to remain effective.

Use Desiccant Dusts

Desiccant dusts like silica aerogel, amorphous silica gel and Dryacide work similarly to diatomaceous earth. These ultra-absorbent formulations also remove moisture from millipede bodies, leading to dehydration and death within 48 hours. Apply light dustings to hidden millipede harborages away from human contact. Follow all label instructions for these professional-grade products. Desiccant dusts provide long-lasting residual activity against millipedes.

Vacuum Regularly

Frequently vacuuming floors, baseboards, vents, pipes and clutter eliminates established pathways of millipede activity. Removing egg cases, larvae, food sources and frass helps reduce infestation levels. Discard the vacuum bag immediately to prevent escaped millipedes from re-establishing colonies. A vacuum with a HEPA filter collects microscopic eggs for total removal. Use vacuum attachments to remove millipedes from cracks and crevices.

Use Low-Impact Insecticides

For severe infestations, low-impact insecticide sprays can kill millipedes on contact while avoiding harmful chemicals. Look for products containing essential oils like peppermint, citrus, clove or rosemary oil which repel and kill millipedes naturally. You can also find insecticidal dusters containing boric acid or diatomaceous earth for broadcast application across large areas. Always follow label directions carefully when applying insecticides. Only use outdoor treatments outside to avoid contaminating food prep surfaces and excessive indoor exposure.

Release Natural Predators

Encouraging natural millipede predators to take up residence in your yard provides free biological pest control. Install habitats for birds, frogs, snakes, centipedes, ground beetles, ants and soil mites which all consume millipedes. Place bird feeders and houses, frog ponds, brush piles and bat boxes to attract predators. Limit use of pesticides outdoors that would repel or kill these beneficial species. Having robust predatory populations outdoors reduces the number of millipedes available to invade the home.

Seek Professional Pest Control

For severe, persistent millipede infestations, professional pest control provides the most effective solution. Exterminators have commercial-grade insecticides, fumigants and comprehensive treatment plans not available to homeowners. They locate all hidden nesting sites, thoroughly treat both outdoors and indoors, and provide ongoing prevention. While professional treatment costs more upfront, in the case of stubborn millipede swarms, this investment can resolve the problem permanently where DIY efforts fail.

Preventing Future Millipede Invasions

Eliminating an existing millipede problem is only half the battle. You also need to take preventative steps to keep new millipedes from invading again down the road:

Install Exterior Lighting

While millipedes avoid sunlight and prefer darkness, installing outdoor lighting repels them from door and window areas at night. Illuminate entryways, porches, patios and the perimeter of your home using sodium vapor or LED bulbs. This deters millipedes from congregating near common entry points after dark.

Clean Gutters and Downspouts

Clogged gutters and downspouts overflow, causing moisture buildup and leaks near the foundation. Routine cleaning keeps them free of debris, ensuring proper drainage away from the house. Eliminating standing water and overflow deters moisture-loving millipedes from colonizing nearby.

Mulch Landscape Beds

Applying a 2-4 inch layer of inorganic mulch like rocks, pebbles or rubber in flower beds, gardens and tree rings creates an inhospitable habitat for millipedes. It removes damp, decomposing matter where millipedes thrive. Be sure to leave a barrier space between the foundation and landscape beds during mulching.

Stack Firewood Away from Home

Always store firewood at least 20 feet from the home’s exterior on a raised platform. Keep it covered from the elements. Avoid stacking cordwood in the garage, crawlspaces, against the house or on the porch or patio. Firewood offers ideal millipede habitat so keeping it distant prevents migrations indoors.

Inspect Potted Plants

Closely examine all indoor and outdoor potted plants to ensure millipedes aren’t hiding in the soil, traveling inside as covert hitchhikers. Quarantine new plants before bringing them indoors. Repot store-bought plants in sterile potting mix. Remove and destroy infested plants to avoid spreading millipedes.

Dehydrate the Yard

Supporting a dry yard environment through proper drainage, limited irrigation, removing heavy vegetation near the home, aerating dense soil, applying sand barrier layers and using dehydrating mulches makes yards less hospitable to moisture-loving millipedes. Take measures to reduce moisture and organic matter across the entire property.

Apply Insecticidal Barrier Treatments

Applying long-lasting insecticide sprays, dusts or granules around the home’s exterior creates a chemical barrier to repel and kill approaching millipedes. Products like Demand CS, Talstar and Bifenthrin provide 3-6 months of residual activity against millipedes when applied to window seals, doorways, siding, weep holes, ventilation openings, porches, patios, and other exterior infestation points. Reapply these barrier treatments semi-annually.


A sudden millipede invasion can be perplexing and aggravating. Despite their mostly harmless nature, having hordes of skittering legs and noxious odors overrunning your home is the stuff of nightmares. Now that you understand what causes millipedes to seek sanctuary in your house along with comprehensive removal and prevention advice, you can evict these uninvited guests and keep them from returning again in the future through proactive control measures. With persistence and dedication to millipede-proofing both indoors and outdoors, you can successfully rid your home of these many-legged menaces for good.

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