The appearance of centipedes in indoor plants can be an alarming discovery, often leading to concern about the health of the plant. While these arthropods are generally beneficial predators in outdoor ecosystems, their presence indoors is understandably unwanted. Centipedes do not typically feed on plant roots or foliage, but their existence in your potted soil is a symptom of underlying conditions that need to be addressed. This guide provides practical, non-chemical methods for safely removing these speedy creatures and establishing a healthier environment for your houseplants.
Confirming the Pest and Understanding the Source
It is important to correctly identify the organism, as centipedes are often confused with millipedes, which behave very differently. Centipedes are characterized by rapid movement, flattened bodies, and one pair of legs per body segment, making their legs appear to stick out from the sides. These animals are carnivorous hunters, indicating they have found a food source in your soil, such as fungus gnats or springtails.
Millipedes, conversely, are much slower, have a rounded, cylindrical body, and possess two pairs of legs on most body segments. They are primarily detritivores, feeding on decaying organic matter like old leaf debris and rotting wood chips. Centipedes are drawn to planters because the soil provides moisture, shelter, and a reliable supply of prey. Overwatered soil or excess organic material creates the damp, dark conditions they seek, allowing both them and their food source to thrive.
Immediate Non-Pesticide Removal Methods
For centipedes seen on the soil surface or the outside of the pot, manual removal is the most direct and simple solution. Since they move quickly, using long tweezers or gloved hands can help capture the visible pests for immediate relocation outside. This is an effective first step for minor infestations.
A more comprehensive method involves flushing the centipedes out of the root ball by submerging the entire pot. Fill a large bucket or sink with lukewarm water, possibly adding a few drops of mild dish soap, and immerse the entire container so the water level is above the soil line.
Centipedes are not aquatic and will quickly move up and out of the soil to escape the water, often drowning or suffocating from the soapy film within 15 to 30 minutes. After the soaking period, allow the pot to drain completely before returning the plant to its location, which is a necessary step to prevent root rot.
Simple trapping techniques can also be used overnight to capture centipedes that are active when you are not watching. Centipedes seek dark, damp shelter during the day, so placing a piece of damp, crumpled newspaper or a slice of raw potato directly on the soil surface will attract them. The next morning, carefully remove the trap along with any hiding centipedes, and dispose of them or release them far away from the house.
Addressing the Soil and Preventing Reinfestation
Eliminating the centipedes’ food source and preferred environment is the most effective long-term strategy for prevention.
Moisture Control and Drying
The soil must be allowed to dry out significantly between waterings, as excess moisture is what attracts the centipedes and the small pests they hunt. A general rule is to let the top one to two inches of soil become completely dry before watering again.
Repotting Severe Infestations
If the infestation is severe or persistent, a full repotting may be necessary to completely reset the environment and remove any hidden eggs or larvae. This involves gently removing the plant from its container and carefully rinsing all the old soil from the roots under a stream of lukewarm water. Discard the old potting mix and any remaining pests. Place the plant into a thoroughly cleaned container with fresh, sterilized potting soil.
Using Diatomaceous Earth
To create a hostile environment on the soil surface, lightly sprinkle a thin layer of food-grade diatomaceous earth (DE) over the topsoil. Diatomaceous earth is a fine powder that causes desiccation in centipedes and other arthropods that crawl across it. Reapply the DE after watering, as it loses effectiveness when wet. Long-term prevention also includes removing all fallen leaves and organic debris from the soil surface, as this material serves as food and shelter.