Published in the Contra Costa Times on October 9, 2004

Q. Will chewing gum work to repel moles?

A. There is no evidence that this old gardener’s tale has any truth to it. The presence of mole hills is irritating to some gardeners, and different items have been jammed in attempts to either kill these animals or to encourage them to move into someone else’s garden. Mole repellent plants, vibrating poles, mothballs, broken glass, urine, ultra-sonic devices, human hair, hot pepper, bleach and thorny branches are only a few of the ‘cures’ that we are asked about. The results are usually ineffective, and can sometimes be dangerous.

Moles are fascinating, solitary animals. They are not rodents, although they are often accused of belonging to that family.  Moles are primarily insectivores. One 5 ounce mole can eat up to 40 pounds of grubs and insects a year—including many of the pests that cause lawn and garden damage. They prefer to tunnel through moist, friable soil with an ample supply food, and in decent soils can tunnel about 18feet/hour! Once the tunnels have been dug, moles can run through them at about 80 feet/minute, which explains how they can out-run the garden hose flush technique. They have very poor sight, but are exquisitely sensitive to smells and to subtle vibrations carried through the soil matrix. Once a year in the spring a litter of 2-6 young is borne. They quickly mature and move out on their own in several months.  Moles aerate the soil a well as providing low cost insect control, and in healthy garden can easily be tolerated.

If you must get rid of the moles, trapping is the only reliable method available. Mole traps are available in hardware stores and nurseries. You will need to determine which of the runways in your yard are currently being used. Water the soil and stamp down several sections, checking daily for new tunneling. Moles dig deep tunnels which are used regularly as well as the shallow surface ones that may only be used occasionally. You may need to probe with a long, pointed stick to locate the deeper tunnels. Follow the instructions that come with the trap closely if you want results. Moles are more difficult to trap than are pocket gophers and some of the other animals that can be occasional problems in our yards.