“We have what seems to be hundreds of earthworms that appear on our driveway, either dead or still living, throughout the day. Why does this happen, and how do we control them?” -Brenda

After a rain, or when humidity is high, it’s very common to see earthworms making their way to the surface of the earth, including driveways and sidewalks. Earthworms breathe through their skin (they don’t have lungs), and they require a balanced level of moisture in order to survive. When the soil is too dry, they burrow deeper to find moisture. When the soil is wet, they move closer to the surface. When there is adequate surface moisture or humidity, they venture out aboveground and look for new places to burrow. The wet weather of spring and fall seems to bring them out in droves.

Earthworms are one of those mixed blessings in the yard and garden. One acre of healthy soil can have as many as a million earthworms! It’s GOOD to have earthworms – they aerate and enrich the soil, move nutrients around, digest and break down organic matter, and improve drainage and soil texture. In fact, earthworms do a better job than any farm or garden practice, and the gardener gets to reap the benefits. However, the downside of having a healthy earthworm population is that they are constantly underfoot during wet weather.

Because earthworms are considered beneficial creatures, most pest-control products have been designed not to harm them. There are currently no products specifically for controlling earthworms, and it’s really not recommended to try to kill them at all. So, the problem of earthworms on the driveway is one that we have to learn to live with (by stepping over them, or sweeping or rinsing them off), rather than control. Inviting more birds to your yard may help – I have several large robins in my yard that are constantly gorging at the earthworm buffet, and I’ve never seen a worm left behind.

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