Controlling Moles in the Garden

Early spring is mole season. The little tube-shaped insectivores with their tiny eyes, invisible ears and broad digging feet prefer being deep underground where they live sight unseen and bother no one, but in the spring, when the subsoil is soaking wet (or still frozen), they move up to just under the soil surface. In areas with rainy autumns, there may a second invasion at that season as well. 

When active near the surface, their constant tunneling (up to 100 feet/30 m a day) pushes up sections of lawn, making mowing almost impossible and ruining any chance of playing badmitten without tripping. They also do a job on perennial beds, uprooting plants which then dehydrate. And the mounds of soil they leave here and there are unsightly. What to do? 

Temporary Pests

All sorts of home products and commercial remedies are recommended for controlling moles and some seem to work … largely because of the fact that moles simply move back underground all on their own when the soil dries out. So, you test a method and cry eureka, certain you have found a solution, but in fact, your treatment might actually have been a total dud: the mole simply left on its own.

Moles are essentially subterranean animals. Rarely do they rise to the surface longer than they have to, just enough time to push a bit of soil out of their upper tunnels. Even then, they generally only come to the surface at night. As a result, you see the damage a mole causes, but rarely the animal itself.

And by the way, moles are generally solitary creatures. Other than for a month or so in the spring when mama mole has her babies with her, all the tunnels you see were likely created by just one mole … or at most, two moles with adjacent territories.

What Moles Want

Know thy enemy. Moles tunneling through your lawn and garden are looking for food. And no, they don’t eat plants or plant roots. Any damage they do to plants is incidental to their search for earthworms, their favorite food. They’ll also eat soil insects, including grubs, beetles and cutworms, plus slugs and snails and even small snakes and baby mice. But they prefer worms. 

No use therefore comes from treating your lawn with an insecticide to eliminate white grubs (a method often recommended). White grubs are only a secondary food source and moles will still frequent lawns where no grubs are present. 

Methods That Don’t Work

The mole’s propensity for apparently disappearing as quickly as it appears (remember, it is actually still there, but now deep underground) has led to all sorts of curious tricks that are supposed to control them. Here are just a few of the duds, mostly products you’re supposed to put into mole tunnels to chase them away or kill them:

• Stick of gum. Juicy Fruit is the usually recommend variety. The theory is that they swallow the gum and it fatally blocks their intestines… but in fact they have no interest in gum;
• Ultrasound devices. These were designed to control rodents. Moles are not rodents, they’re insectivores;

• A pinwheel stuck into the tunnel (the vibrations are supposed to chase moles away); 
• Mole repellant plants. Caper spurge (Euphorbia lathyris), garlic and castor bean (Ricinus communis) are recommended, but they have no effect whatsoever. Remember: moles don’t eat plants and couldn’t care less what you grow;
• Cat litter;
• Cayenne pepper;
• Dryer sheets;
• Rodent traps;
• Rodent bait;
• Pieces of broken glass;
• Gravel (even if you fill a tunnel with gravel, the mole will just dig another one);
• Flooding their tunnels with water;
• Smoke bombs, homemade or commercial: there are just too many openings in a mole tunnel for this to work.

Methods That Do Work

Putting in a Mole Barricade

Dig a trench roughly 6 inches (15 cm) wide and 2 feet (60 cm) deep and fill it with densely packed gravel. Or insert wire mesh into the ground to a similar depth. While this may actually work (if you put it in the right place; you’ll want to keep the mole out of your lot, not trap it inside!), it’s a hell of a lotta work. You’d really have to hate moles with a vengeance to try this one.

Fake Worms Laced with Poison

Yes, scary, isn’t it? Most contain bromethalin, toxic to mammals, including humans and pets. Be verrrry careful if you want to try this one. The idea is to insert the bait into an active tunnel … and hope for the best!

Drain Your Lot

Moles tend to stay nearest to the surface in soils that are too humid, that is, those with a drainage problem. Installing proper drainage can help with a lot of things (including possible damage to your home!), but may also allow moles to stay deep underground and thus keep out of your way.

Mole Trap

You can find these in most hardware stores. Note that most of these are kill traps: the mole will not come out of this encounter alive. 

You have to locate an active tunnel, then install and set the trap. To find an active tunnel, lightly step on the tunnels to collapse them slightly. Come back a few hours later and those that have pushed up again are active ones. There is no need to bait a mole trap: it’s activated by physical contact. If the mole pushes through it … well, you don’t really need to know that part.

Call in an Exterminator

Not all exterminators want to deal with moles, but those that do will probably use a mole trap, described above. 

The Pitchfork Method

Locate an active tunnel and stand near it with a pitchfork at the ready. When you see the soil start to move, you’ll know what to do. (Sensitive souls should definitely skip this one.)

Or Live and Let Live

A truly laidback gardener method. Just learn to live with moles. That can be hard to do if you’re a lover of perfect lawns, but lawns do recover. And the damage to other gardens is rarely severe. And again, in most gardens, they’re present for such a short period. So, if you’re able to put up with them…

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Moles: they’re fascinating creatures, but they can admittedly be a major annoyance. How you deal with them is up to you!