Groundhogs, also known as woodchucks, are a common source of frustration for homeowners and gardeners across North America because of their extensive burrow systems and appetite for vegetation. The damage caused by their digging and feeding often sends people searching for quick, low-effort remedies to remove the pest. One of the most frequently suggested, yet often misunderstood, home remedies involves placing mothballs near or inside groundhog burrows. This approach is rooted in the belief that the strong odor of the chemicals will drive the animals away from the property.
The Direct Answer: Do Mothballs Deter Groundhogs?
The belief that mothballs effectively deter groundhogs is an anecdotal solution unsupported by scientific evidence. Groundhogs are adaptable animals that do not respond permanently to the chemical odor of mothballs placed near their dens. While the initial strong scent may cause temporary avoidance, the animal often habituates to the chemical quickly.
The groundhog typically responds to the odor by simply moving the entrance or exit of the burrow system a short distance away. Since the burrow is the groundhog’s primary defense, a slight annoyance will not cause it to vacate a prime feeding area. Effective deterrence requires a method that forces a permanent change in the animal’s behavior, which a static, dissipating scent cannot achieve.
Hazards and Misuse of Naphthalene
Mothballs contain active ingredients, most commonly naphthalene or paradichlorobenzene, which are classified as pesticides. These chemicals are registered solely for controlling clothes moths and other fabric pests within sealed, airtight containers.
Scattering mothballs outside to repel wildlife constitutes a misuse of a registered pesticide. This improper application is illegal because it violates the instructions printed on the product label, mandated by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The outdoor use of these chemicals poses a serious risk to humans, domestic animals, and the environment.
Children and pets are at risk of accidental ingestion, which can lead to serious health issues, including hemolytic anemia. Furthermore, the chemicals contaminate the soil and groundwater as they slowly dissolve and sublimate into the air. The EPA has classified naphthalene as a possible human carcinogen. Using mothballs outdoors pollutes the local ecosystem without providing reliable pest control benefit.
Effective Groundhog Control Strategies
Homeowners should focus on proven physical and habitat management strategies rather than ineffective chemical remedies. The most reliable long-term solution is exclusion, which means physically blocking the groundhog’s access. Since groundhogs are excellent diggers and climbers, a simple fence is often insufficient.
A successful exclusion fence should be constructed from sturdy material like hardware cloth or welded wire and stand at least three to four feet high. The fence perimeter requires an underground barrier to prevent burrowing. This is achieved by burying the fence material at least 12 inches deep or by creating an L-shaped footer that extends underground for at least 10 inches, bent outward.
Habitat modification is another effective strategy. Groundhogs seek cover in tall grasses, dense vegetation, and debris piles, so keeping the area around a garden or building foundation clear of these shelters is helpful. Removing immediate food sources, such as promptly harvesting ripe vegetables and securing compost bins, also draws the animals away.
For short-term management, commercially available, EPA-approved animal repellents can be used, particularly those containing capsaicin or putrescent egg solids. These products must be applied frequently according to their labels to maintain a deterrent effect. If exclusion fails, professional trapping and removal services may be the most efficient final option, always following local wildlife regulations.