Ants invade potted plants for food and moisture, and some species will use the plant’s soil as a nesting site. An ant invasion may indicate the presence of other plant pests, too, because honeydew-producing insects such as scales, aphids and mealybugs provide a food source to ants by excreting a sweet liquid on the plant. Remove ants from plant containers, and then prevent re-infestation through cultural and chemical control. It’s not feasible to remove all ants from outdoor areas, but indoor and outdoor control measures will protect potted plants from infestations.
Move ant-infested indoor plants to an outdoor area.
Rinse the plant’s foliage with water to dislodge ants and aphids, and pick scales and mealybugs from foliage by hand. For severe infestations of honeydew-producing insects, apply an insecticidal spray using the product manufacturer’s instructions.
Remove ant nests from the soil by mechanical removal, water submersion or chemical control. Dig out the nest and dispose of it in a plastic bag, or dump all soil into a plastic bag and repot the plant in fresh potting soil. For water submersion, set the plant container inside a larger, deeper container of standing water and allow it to sit for 20 minutes. Flood the plant repeatedly if necessary to drive all ants away, or add two tbsp. of insecticidal soap for each quart of water to kill ants in the first 20-minute session.
Return the plant to its indoor setting if desired.
Pour diatomaceous earth around the outside of the plant container to create a barrier.
Sprinkle mint leaves and flowers around the plant to repel ants, or cultivate mint plants near outdoor plant containers.
Stop indoor ant infestations by sealing foods, caulking cracks in the building and placing ant bait stations in areas where ants remain active. Place bait stations 10 to 20 feet apart beneath the plants in infested outdoor areas, as recommended by the University of California’s Pest Management Program.
Kill any lone ants you see wandering through your home, as recommended by Virginia Tech, because these ants scout for food and nesting sources for a colony.
Repeat control measures for honeydew-producing insects if they reappear on indoor or outdoor plants.