Pocket gophers are common burrowing mammals that damage lawns and gardens by feeding on plant roots and creating extensive tunnel systems. Their presence is often identified by crescent-shaped mounds of soil. Many homeowners turn to home remedies, and the belief that garlic can repel these pests is a popular, non-toxic solution. This examination looks into gopher behavior and the science behind garlic’s strong odor.
Gopher Dietary Habits
Gophers are strict herbivores, primarily consuming roots, tubers, and other succulent underground parts of plants, such as grasses and alfalfa. They encounter food sources while excavating their tunnel networks. Gophers tend to avoid plants in the Allium family (onions, chives), even though garlic is a root vegetable. This avoidance is due to the plant’s defense mechanism. Garlic contains powerful organosulfur compounds that create a pungent odor and intense flavor, making it an unappealing food source. Gophers will bypass garlic in favor of less offensive vegetation.
Garlic’s Effectiveness as a Deterrent
Garlic’s potential as a gopher deterrent relies on the strong, irritating smell produced by its sulfur-rich compounds. When garlic is crushed, the enzyme alliinase converts alliin into allicin, which breaks down into volatile compounds, including diallyl disulfide (DADS). This compound creates a potent odor highly irritating to the sensitive olfactory systems of burrowing rodents. The theory suggests that introducing this odor makes the tunnel system inhospitable, forcing the gopher to abandon the area. Commercial repellents often use concentrated garlic oil containing these sulfur compounds. While anecdotal reports suggest reduced gopher activity, consistent scientific evidence is limited. University research often finds that scent-based repellents lack reliable proof of long-term effectiveness in field conditions. The main challenge is maintaining the potency of the volatile compounds throughout the complex gopher tunnel system.
Methods for Applying Garlic
Gardeners testing garlic’s efficacy have several methods for introducing the odor into the gopher’s environment.
Planting Cloves
One technique is to plant whole garlic cloves strategically around vulnerable plants or along garden borders. The living Allium plant provides a continuous, milder underground scent barrier.
Direct Insertion
A more direct approach involves inserting peeled and crushed garlic cloves directly into active burrow entrances. Crushing the cloves releases the maximum concentration of diallyl disulfide, creating an immediate, strong odor within the tunnel.
Liquid Application
Alternatively, a garlic spray or “tea” concentrate can be made by boiling crushed garlic in water. This liquid is then poured into the burrow system to distribute the repellent scent more widely through the soil structure.
Alternative Gopher Control Strategies
Because the effectiveness of garlic as a long-term deterrent can be variable, more reliable methods are often necessary to protect a garden from gophers.
Exclusion
Exclusion is one of the most dependable strategies, involving the installation of physical barriers like gopher wire or hardware cloth. Burying mesh at least eighteen inches deep and extending it above the soil line can prevent gophers from accessing valuable planting areas or individual plants.
Trapping
Trapping is also widely regarded as one of the most effective physical control methods for small areas or low-level infestations. Traps are placed directly into the main runway of the tunnel system, which is usually located by probing the soil near a fresh mound.
Other Non-Lethal Options
Other non-lethal options include the use of granular products containing castor oil, which is known to be unpleasant to gophers, and the application of sonic or vibration devices. However, these devices often yield inconsistent results.