Finding ants in potted plants, whether indoors or on a patio, is common and signifies the insects have found suitable shelter and a potential food source. Ants are drawn to the loose, protected soil of containers, which offers an ideal environment for nesting and tunneling. They may also be farming pests like aphids or mealybugs, which secrete honeydew they feed on. Addressing this problem requires a practical, multi-step approach focused on safely removing the colony and implementing long-term prevention.
Non-Invasive Physical Removal Techniques
For a significant ant colony residing deep within the soil, physical removal methods are the most direct first step before applying treatments. The submersion, or “dunking,” method is highly effective for forcing the ants to evacuate the pot. To perform this, submerge the entire pot up to the rim in a large container of water, allowing the water to cover the soil surface completely.
Ants cannot survive underwater and will quickly stream out of the soil to escape the rising water level. The pot should remain submerged for 15 minutes to an hour to ensure all ants, including those deeper in the root ball, have been flushed out. Once the ants have left, remove the pot and let it drain thoroughly before returning it to its location.
If the infestation is severe and the ants are deeply entrenched, repotting the plant with fresh soil may be necessary. Carefully slide the plant out of its container and dispose of the infested soil away from other plants, such as by sealing it in a bag. Gently hose off the roots to dislodge any remaining ants or insect eggs before replanting it in a cleaned container with new potting mix.
Simple Household Solutions for Eradication
Once the bulk of the colony has been physically removed, household solutions can treat remaining ants and discourage their return. A simple, low-toxicity solution involves a mild soap and water drench applied directly to the soil. Mixing one to two teaspoons of liquid dish soap with one quart of water creates a solution that breaks the surface tension, causing ants that come into contact with it to drown or dehydrate. Pouring this solution over the soil saturates the medium and kills any remaining ants or larvae. Follow the drench with a thorough rinse of clean water to flush the soap residue before allowing the pot to drain completely.
Diatomaceous Earth (DE), a fine powder made from the fossilized remains of diatoms, is another effective physical control. Food-grade DE works by microscopically scratching the ant’s exoskeleton, leading to fatal dehydration. This powder should be dusted lightly over the surface of the potting mix, but it is only effective when dry, requiring reapplication after watering.
Natural scents can also be used as repellents, as ants rely heavily on pheromone trails for navigation. Sprinkling cinnamon powder or used coffee grounds directly onto the soil surface can disrupt these scent trails, confusing the ants and deterring them from crossing the barrier. Similarly, the strong aroma of citrus oils, such as those found in blended citrus peels, can be used as a spray around the pot to repel the insects. These methods create a hostile environment that encourages the ants to move elsewhere.
Long-Term Prevention Strategies
Preventing future ant infestations involves modifying the environment to make the potted plant less appealing as a nesting site. Ant species that nest in pots often prefer loose, dry soil, so maintaining adequate soil moisture can deter them. However, avoid overwatering, as overly saturated conditions can harm the plant.
A simple and effective physical barrier, often called a “moat,” can be created by placing the entire pot in a saucer filled with water. Ants cannot swim and will be unable to cross this water barrier to reach the soil. Maintain a consistent water level in the saucer and regularly refresh the water to prevent it from becoming a breeding ground for mosquitoes.
Another prevention strategy is to eliminate potential food sources, which often means addressing other plant pests. Ants are strongly attracted to the honeydew produced by sap-sucking insects like aphids and mealybugs. Controlling these secondary pests with insecticidal soap or neem oil removes the ants’ primary food incentive, causing them to abandon the pot.