Every fall, it’s the same scene: a big spider crossing the living room floor, another in the bathtub, webs in the corners of the windows. It’s not your imagination: spiders are more visible in the house at this time of year. Here’s what draws them in, and how to keep them out without spraying the whole house.
Why spiders show up in the fall
Most of the large spiders you see in the house in September and October don’t live there. They are outdoor spiders wandering in by accident. As nights cool down, they look for shelter, and many males roam in search of a mate. A gap under a door or around a window is enough to let them in.
According to Iowa State University Extension, these accidental invaders, like wolf spiders, usually don’t survive long indoors and can’t reproduce there. The air is too dry and there is not enough to eat.
What attracts them inside
- Insects: spiders follow their food. Outdoor lights that attract moths near the door bring spiders with them.
- Clutter: boxes in the basement, piles of clothes, a crowded garage offer perfect hiding spots.
- Gaps: worn door sweeps, torn window screens, holes around pipes and cables.
- Vegetation against the house: shrubs, ivy and firewood touching the walls act as bridges.
How to keep them out
- Seal the entrances: caulk cracks, replace worn weatherstripping and door sweeps, repair screens.
- Switch outdoor lights to yellow “bug” bulbs, or turn them off when not needed: fewer insects means fewer spiders.
- Clear a strip around the foundation: trim shrubs, move firewood and leaf piles away from the walls.
- Vacuum regularly corners, ceilings and behind furniture, including webs and egg sacs.
- Use sticky traps in the basement and garage to catch wanderers and see where they come from.
Fall is also the season of spider webs on porches and around outdoor lights. Knock them down regularly with a broom before they multiply. A spider in the house? Slide a glass over it, slip a sheet of paper under it and put it outside.
The limit
Peppermint oil, vinegar or chestnuts are often recommended online, but there is no solid evidence they keep spiders away for long. Outdoor insecticides don’t help much either, according to Iowa State. The real fix is mechanical: sealing gaps and reducing insects. And remember that nearly all house spiders are harmless and even useful: they eat other bugs. In the US, the black widow and the brown recluse are the exceptions to watch for.
Spiders aren’t the only ones moving in now. Rats are too, as we explained in where rats go in winter, and so are stink bugs. At the entrance, a simple habit also helps: vinegar on the front door.
A tube of caulk, a new door sweep and a yellow bulb by the door. That’s the trick.
