What Is the Most Effective Method for Keeping Spiders Out of the House & for Getting Rid of Them?

Spiders in Houses

• Spiders of various species get into houses through openings, such as small cracks in foundations and gaps around windows. Humans also unwittingly carry in spiders and spider egg sacs on various items, particularly plants and firewood. There is no single effective method for getting rid of spiders; employing a combination of measures works best, according to the Ohio State University Extension. Measures include eliminating spider entryways into homes, cleaning out household clutter and applying insecticides, especially according to whether indoor spiders stay in a web or roam around the floor for prey.

Removing Access

• Check around the house's foundation and remove any vegetation, trash or heaps of other materials, including wood, placed against it. This decreases the chances of spiders living near homes and eventually moving indoors. Keep lighting fixtures -- which attract spiders looking for insects to eat -- away from windows and doors, notes the University of California Statewide Integrated Pest Management Program. Ensure that door and window screens fit tight, caulk or seal any cracks around windows and doors, add weather stripping and door sweeps, and cement cracks in foundations. These measures also keep out insect prey for spiders. Regularly sweep or hose down webs and spiders off of the house's exterior. Insecticides are not reliably lasting in changing outdoor weather and air conditions, if applied only to the ground or wall. But, insecticide can be used effectively if sprayed directly on outdoor spiders, which will then be dead in minutes.

Eliminating Living Areas

• Remove items that attract spiders' in indoor areas by getting rid of old boxes, old clothing and other unused clutter in closets, basements and attics. Boxes that hold necessary items should be placed off of the floor and away from walls, to make them harder for spiders to get to. Frequently vacuum or dust areas where you see spiders, spider webs or egg sacs. Immediately place the vacuum bag in the trash outdoors. Place sticky traps in these areas.

Insecticides

• Study spider activity in your home. Spiders that move about frequently, looking for and chasing prey, can be eliminated with insecticides sprayed on the floor. The Ohio State University Extension recommends applying wettable powder or microencapsulated, slow-release, residual insecticides to the areas where hunting spiders are found indoors.

  Web-builders spend most of their time in their web. Spray insecticides meant for spiders directly on the spider if it is in the web. A non-repellent insecticidal dust also clings to the web and will eventually come into contact with the spider.

  Insecticides do not reach eggs in egg sacs. Remove sacs with a vacuum sweeper and immediately dispose the bag in the trash outdoors.