The appearance of molehills and surface tunnels across a garden or lawn is a frustrating experience for any homeowner. The resulting damage to turf and plant roots often prompts a search for quick remedies. However, many conventional methods are ineffective or cause unnecessary harm to the animal and the environment. This article focuses on non-lethal, humane strategies that encourage moles to relocate naturally.
Understanding Mole Activity in the Garden
Moles do not consume plants; their diet consists primarily of earthworms, grubs, and other soil-dwelling invertebrates. These mammals have an extremely high metabolism, requiring them to consume 70% to 100% of their body weight daily. This constant need for food drives their relentless tunneling, which is the sole reason for the visible damage on your lawn.
Moles create two types of structures. The conical mounds of loose soil, known as molehills, result from the mole excavating deeper, permanent tunnels, often 12 to 18 inches below the surface. The raised ridges visible just beneath the grass are the shallow, temporary surface runs where the mole actively hunts for food. Identifying these active feeding tunnels is important for effective humane control.
Sensory Methods for Humane Repulsion
One non-lethal strategy uses the mole’s heightened sense of smell and taste to make the environment unappealing. Castor oil-based products are widely used because the oil coats the earthworms, tainting the mole’s primary food source. This foul taste encourages the mole to move its foraging activities elsewhere.
These repellents are available in granular and concentrated liquid forms, requiring thorough watering to penetrate the soil effectively. After application, irrigate the treated area with one-half to one inch of water to carry the castor oil deep into the tunnels. For ongoing protection, reapplication is necessary every two to three months, or immediately following heavy rainfall.
Planting species that emit strong odors or have toxic compounds is another sensory approach, though their effectiveness is limited. Daffodils contain the toxic alkaloid lycorine, and marigolds release thiophenes from their roots, which may discourage moles and some insect food sources. While these plants can add a protective border, their success is variable and they should not be relied upon as a sole deterrent.
Ultrasonic and vibratory devices inserted into the ground attempt to create an uncomfortable environment by mimicking vibrations. However, the efficacy of these devices is often debated and depends on soil conditions and the depth of the tunnels. Moles are adaptable and may quickly become accustomed to the constant noise, rendering the devices ineffective over time.
Physical Barriers and Habitat Changes
Creating physical exclusion zones and modifying the habitat are reliable long-term humane solutions. To protect specific garden beds, install a physical barrier made of galvanized hardware cloth or metal mesh around the perimeter. This barrier needs to be buried 24 inches deep to block the moles’ access.
The bottom of the mesh should be bent outward at a 90-degree angle, forming an “L” shape, to prevent the moles from tunneling beneath the barrier. This labor-intensive method provides a permanent defense for vulnerable areas.
Environmental modification focuses on reducing the food source, making the area less attractive to the highly-metabolic mole. Eliminating the grub population through preventative insecticide applications in late spring or early summer removes one of the mole’s food staples. Products containing active ingredients like imidacloprid or chlorantraniliprole are effective when applied and watered in properly.
Earthworms are the mole’s preferred food source, and eliminating all earthworms is neither desirable nor possible. Grub control is best utilized as part of a multi-faceted approach, making the garden less appealing. Professional live trapping and relocation should be approached with caution, as relocated moles often face a poor chance of survival due to their territorial nature and high metabolic demands.
Non-Humane and Ineffective Control Measures
Common home remedies and commercially available products are often ethically questionable, ineffective, or dangerous to non-target animals. Flooding tunnels with water is a frequently attempted method that is rarely successful because moles are strong swimmers and can quickly block off flooded tunnels or dig new escape routes. This practice is also harmful to the soil structure, leading to waterlogging and root rot.
Gassing or fumigation products are not recommended due to their low efficacy and toxicity risk. Mole tunnel systems are extensive and porous, meaning the gas often dissipates before reaching the mole, especially in shallow surface runs. Many fumigants are restricted-use pesticides that require a licensed professional for safe application.
Toxic baits, often designed to look like a mole’s natural food, are discouraged because they pose a significant risk of secondary poisoning. Pets, birds, and beneficial predators can be harmed by consuming the poisoned mole. Since moles prefer live earthworms and insects, they often ignore the baits, rendering the poison ineffective.