Getting to Know Spiders

Many people find spiders repulsive and scary, yet the majority of spiders are harmless and beneficial. Spiders make a very significant contribution to insect control.

The Good Side of Spiders

Spiders play an important role in controlling insect populations. An arachnologist (a person who studies spiders) in the United Kingdom once calculated that the weight of insects eaten by spiders in that country every year exceeded the weight of the people who live in the U.K.

Some gardeners encourage spiders to live in their gardens to kill unwanted pests. Using mulches helps spiders by giving them habitat with a moderate microclimate. Planting caraway, dill, fennel, cosmos, marigold, or spearmint also encourages spiders.

Potential Threat?

Most spiders are not poisonous to human beings. There are about 3,000 different spiders in North America, but only a few of them cause problems for people. (See Identifying Spiders)

If you are bitten, try to capture the spider that bit you if you can catch it quickly and safely. Later, if needed, you can get an accurate identification of the spider.

Preventing Spider Problems

There are many ways to make your home less appealing to spiders.

• If there are cracks in your foundation or around windows and doors, seal them up. 
• Check places where water pipes and electrical lines enter your house, and caulk any openings. 
• Keep woodpiles and debris away from your house. 
• In storage areas, put boxes up off the floor and away from walls. Seal boxes with tape to keep spiders from living inside them. 
• In general, cleaning up clutter will mean you have fewer spiders.
• Pruning vegetation away from your house and keeping the area next to the foundation clear will also make your house less attractive to spiders.  
• Outdoor lighting sometimes attracts insects, which in turn attracts spiders. You can move outdoor lighting away from windows and doors if this is a problem around your home.

Removing Spiders

• You can remove a spider from inside your house by putting a jar over it. Then slip a piece of paper under the jar so that the opening is sealed, pick up the jar, and take the spider outside.
• A good vacuum cleaner easily removes spiders and their webs from your house. Since spiders have soft bodies, they usually don't survive vacuuming. A broom is also a useful tool for moving a spider outside.
• Crushing spiders with a fly swatter, rolled up newspaper, or your shoe are other simple ways to deal with unwanted spiders.

Chemicals Are Ineffective

Using a pesticide is not a good solution to spider problems. "Insecticides will not provide long-term control" of spiders, according to the University of California, "and should not generally be used against spiders outdoors." Inside, "control by spraying is only temporary unless accompanied by housekeeping." Washington State University Extension has a similar perspective:  "Most spider problems can be solved without the use of chemicals."

Summary

Overall, spiders are far more beneficial than they are dangerous. The benefits we realize from spiders preying on insects, mites, and other spiders far outweigh the low potential health hazard to humans.

Chemical spraying may well be be more dangerous and less effective than you think, so use simple chemical-free techniques and be creative in controlling spider habitat.

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Also see: Identifying Spiders