Gophers are common subterranean pests that rapidly damage lawns and gardens by creating extensive tunnel systems and feeding on plant roots. Castor oil is a non-lethal, natural deterrent that creates an unpleasant environment, encouraging gophers to relocate their burrowing activity elsewhere. This approach avoids harsh chemicals and offers a simple way to manage infestations. This guide details how to prepare and apply a castor oil repellent.
Preparing the Repellent Mixture
Creating an effective castor oil repellent requires combining the oil with an emulsifier to ensure it mixes thoroughly with water. Oil and water naturally separate, but the addition of liquid dish soap allows the oil to remain suspended in the water. This suspension is necessary for proper application and soil penetration before the mixture is diluted to create the final repellent.
A common and effective ratio involves mixing one part castor oil with one part liquid dish soap to create a concentrate. For instance, mix a half cup of castor oil with a half cup of dish soap until the solution becomes uniformly blended and slightly foamy. The soap molecules encapsulate the oil droplets, preventing them from coalescing when mixed with water.
Once the concentrate is prepared, it must be significantly diluted before application to the soil. A typical dilution rate is two tablespoons of the castor oil and soap concentrate mixed into one gallon of water. This creates a solution strong enough to irritate gophers but safe for your lawn and plants. The strong smell and taste of the castor oil are highly offensive to gophers, and if ingested, the oil acts as a digestive irritant, prompting the animals to leave the area.
Applying the Mixture to Gopher Tunnels
Successful application relies on directly targeting the gophers’ active burrow systems to saturate the soil surrounding their tunnels. Begin by identifying the primary areas of activity, which are typically marked by fan-shaped mounds of freshly excavated dirt. Locating the main tunnel entrance, usually found slightly off-center of the mound, is the first step before treating the area.
There are two primary methods for delivering the repellent mixture into the ground. For direct, localized treatment, the diluted solution can be carefully poured into the main tunnel openings. Saturate the holes and the immediate surrounding soil, ensuring the liquid flows deep into the burrow network. This method is effective for treating a small number of distinct, active mounds.
For broader coverage across a lawn or a larger infested area, a hose-end sprayer attachment is a more practical tool. Fill the sprayer reservoir with the concentrated mixture—not the pre-diluted solution—and set the dial to the appropriate rate for a heavy application. As you spray, the device automatically mixes the concentrate with the water from the hose, distributing the repellent evenly across the turf. Saturate the area thoroughly so the oil penetrates several inches into the soil, contaminating their food sources and travel paths.
Monitoring and Reapplication Strategies
The goal of the castor oil treatment is to encourage gophers to move away, not to eliminate them within the treated area. After the initial application, monitor the yard for signs of new activity, which is the primary indicator of the treatment’s success or failure. Look for the appearance of new mounds or the plugging of previously open holes, as these suggest the gophers are still active or attempting to repair their system.
Because the repellent’s effectiveness is based on the residual presence of the castor oil in the soil, reapplication is necessary over time. Heavy rainfall or extensive watering can dilute the product, making its odor and taste less potent to the gophers. If you notice new mounds or tunnels developing, a repeat application of the diluted solution should be performed immediately to reinforce the barrier.
A general maintenance schedule involves reapplying the repellent every two to four weeks, or immediately following significant rain events, to maintain a consistent deterrent. Once gopher activity has ceased for a period of several weeks, you can reduce the frequency of application. The continued presence of the castor oil barrier is what ultimately conditions the gophers to seek a permanent home elsewhere.