I admit to being an arachnophobe. Even though intellectually I know how helpful spiders are in the garden, I still get the shakes and run screaming when I see them. Still, we can change, right? I’m doing better. In fact, I’ve struck up an arachnid pact (well, it’s one-sided, but still…)—any spider in the garden is welcome to stay and make itself at home. Any spider that dares infiltrate my home? Let’s just hope my husband is around to rescue it.
In return for my beneficence, I expect some payback. That garden spider is tasked with taking care of any harmful pest infestations. Happily, I can have my garden and the spiders can have their lunches. All spiders are predators, and never feed on plants. That’s a pretty sweet combination.
Spiders are excellent gardening companions. In fact, they’re the most important land predator, eating tons of insects that would otherwise drive us buggy. Unlike beneficial insects, they spend the winter as adults, rather than eggs. Thus, they are on hand to start munching the minute those aphids and grasshoppers hatch. Unfortunately, spiders don’t distinguish between “good” and “bad” bugs, consuming them all with equal enthusiasm. That’s a small price to pay for such efficient extermination services. (Here you see a spider eating a bee.)
If spiders are so wonderful, it follows that we should want more of them in our gardens. Like all animals, spiders need food and shelter. We can accommodate those needs, thus increasing their population. Mulch provides plenty of hidey-holes, perfect for lurking. At the same time, it increases humidity at ground-level, something spiders appreciate.
Being overly neat may help the yard look orderly, but spiders (and birds and other wildlife) prefer a more natural look. Offer your garden helpers a sheltered place to spend the winter by leaving some areas un-tilled and un-mowed. While not all spiders build webs, many do, and it will benefit you to provide a place where they can spin their traps unmolested. Vertical stalks, fences, and branches are some useful supports for web-building.
It should be obvious—avoid spraying pesticides, especially those that kill spiders. Even non-lethal sprays kill the insects that spiders feed on. If we want spiders and other biological controls in our yards, we must be willing to put up with some insect prey. The key here is balance.
Spiders do have their downside. While most species here in Colorado are harmless to humans, we do have black widows. In the past decade, I’ve seen several in my house and yard. Most people will recognize the female widow spider, with her round black body and red hourglass underneath. (The much smaller males are not dangerous, and go mostly unnoticed.) I have no qualms about killing widow spiders. Their bite, though rare, can cause a person to feel miserable for months, and I happen to be allergic to the antivenin. Widows are the only poisonous spiders in the Pikes Peak area.
Other spiders can bite, but their venom is not toxic to humans. That’s a relief to me. While I appreciate all that they do for me, I’d prefer not to get too closely acquainted. They still give me the creeps.
For more information on spiders commonly found in Colorado, see the CSU Extension fact sheet.