Getting rid of moles can be tricky in that they live underground in large tunnel networks. To get rid of them, both ultrasonic repellers and traps are effective, although ultrasonic repellers are the only lasting solution to your mole problem. You can kill your resident mole, but if your garden remains an attractive environment, another one might move in.
Rarely seen, moles live solitary lives constructing networks of tunnels, which provide shelter and act to trap unsuspecting worms.
Moles are perfectly adapted to life underground, owing to three adaptations. Moles’ blood cells have a special form of hemoglobin with a higher affinity to oxygen, which allows them to endure their low oxygen environment without ever surfacing. They are covered in sensory hairs that allow them to navigate their low-light environment and have spadelike claws for digging.
Similar to a human breaststroke, moles use a fore-and-aft motion to construct tunnels, using their back legs to push materials through tunnels. Evacuated soil is pushed through vertical tunnels forming surface mounds or molehills.
A mole’s tunnel network includes both permanent (nests and highways) and semi-permanent tunnels (shallow channels near the surface where most food can be found). Their tunnel system can be several hundred feet and moles may work different portions, digging up to 15 feet an hour.
Moles are attracted to damp, fertile soil, where their primary food source (earthworms) resides. During times of drought moles will migrate towards irrigated soil or otherwise dig deeper in search of moisture.
Protecting Your Lawn
Watering should be kept to a minimum to prevent attracting moles. Lawns will suffice on one-two inches of water per week.
Prior to installing new turf, special netting can be laid to form a barrier between the topsoil and layers below.
As moles will only enter areas deep enough to tunnel, situating you lawn in shallow soil is recommended.
Primrose recommends ultrasonic deterrents as the permanent solution to your mole problem. You can kill a mole with a trap, but all it does is make room for another.
Ultrasonic devices work by emitting low frequency bursts, inaudible to humans, but audible to moles, who confuse the bursts for predators and other moles, and hence quickly vacate the area, moving to other parts of their tunnel network.
Mole repellers are simple to set up, all you do is place them between your house and the mole hills, pushing them back whence they came.
Primrose stocks both battery and solar powered models. Solar powered models work in nearly all situations, however if you have a north facing garden, or are concerned about a lack of sunlight, we stock an all year round deterrent kit composed of a solar-powered model and a battery-powered model, with the latter model working as backup.
Our brand new 4 stake solar chaser has been developed in response to limitations with previous designs. Complete with a 1200mAh battery backup, which can also be charged by USB, the device will remain powered for four days without direct sunlight. With four stakes, you can create a wider barrier, ensuring moles are shepherded more effectively.
Key to effective trapping is to avoid contaminating your traps with human scent. Moles have excellent smell and will avoid suspect areas. Thus, you should only buy traps you are sure haven’t been touched by humans and use disposable gloves when setting up traps.
There are three types of traps: tunnel, claw and spring. Tunnel and claw traps trigger when a mole moves through the tunnel disturbing a plate, while spring traps trigger when the mole goes to unblock its tunnel, triggering the tongue. Thus, with the former the tunnel must be free of debris, while with the latter it must be blocked.
Claw traps are easy to locate as the handles remain above the soil. You can see if its triggered as the handles will be splayed apart. Tunnel traps are completely covered in soil and are thus perfect for areas with livestock/pets present. A downside is that they will need markers to locate, and it is difficult to know if they are triggered.
Mole traps need to be nested within a tunnel, preferably one of the frequented highways. You can locate a tunnel by pushing a sharf into the soil between two mole hills. When you no longer feel pressure, you have discovered a tunnel. Creating holes in multiple tunnels can be used to find the best location for your trap, as areas it repairs are likely frequented.
Once you have decided on the optimal placement, dig a hole no wider than the tunnel’s diameter. Be careful not to disturb the tunnel floor as a mole may go under the trap. If you do, firm it up.
Next, place the trap, so the trigger ring goes across the run, no more than 2cm above the floor. Test the trap, so you are sure the placement is correct. With claw traps, you are blocking the tunnel, so as the mole moves the debris it touches the tongue, causing the claw to close.
Once you are happy with the placement, replace the turf, but not so tight as the trap won’t trigger. (Tunnel traps should be completely covered with turf). Cover any gaps where light may be let in with grass and place a plant pot over the trap to prevent tampering. With tunnel traps place markers so you can easily locate your traps.
Much of the above applies to humane mole traps, although their effectiveness is disputed.
Castor oil coats mole’s prey, rendering them distasteful, causing diarrhea, and forcing them to leave for new pastures. It is a common ingredient in mole repellent granules.
You can create your own spray from a mix of unrefined castor oil, dishwasher liquid and water. To start, blend 100ml of castor oil with 50ml of dishwasher liquid. Then add this to 100ml of water and blend again. This can be added to 4L of water, which will cover 90msq. It is only effective in areas that aren’t extensively irrigated and may need to be reapplied. The solution remains effective for 30-60 days.
Alternatively, you can buy aluminium ammonium sulphate based sprays, which is toxic to mammals.
Mole Deterrent Plants
Some swear by Euphorbia lathyris, which root exudates supposedly scare off moles. Be sure to remove the flower heads come spring, or it will spread rapidly.
Mole deterrent bulbs remain a bestseller and supposedly secrete a smell, undetectable by humans, but horrible to moles.
Broken glass, razor blades, barbed wire, thorns have all be used to try and deter moles. These methods are probably more dangerous to gardeners. Moles will simply circumvent by blocking off those tunnels and digging new ones.
Insecticides will poison the groundwater, kill beneficial soil organisms and harm desirable wildlife.
Coinciding with Moles
The topsoil moles bring up are perfectly structured granular peds, which constitute the perfect potting mix. Moles help with drainage, which can be useful if you have clay soil, which is prone to be waterlogged. Molehills can be hidden with a switch to informal planting.
Jorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!
His ideal afternoon would involve a long walk, before settling down for scones.
Jorge is a journeyman gardener with experience in growing crops.