How to Get Rid of Millipedes in Houseplants

Discovering small, worm-like creatures in your houseplant soil is a common event. These guests often appear without warning, leaving you to wonder if they pose a threat to your indoor garden. Understanding their identity is the first step toward managing their presence. This guide will help you identify these creatures, understand why they appear, and provide methods for addressing them.

Identifying Millipedes and Their Impact

To address the creatures in your plant’s soil, you first need to confirm they are millipedes. These arthropods have dark brown or blackish, cylindrical bodies with many segments. Each body segment has two pairs of short legs underneath. When disturbed, a millipede’s most telling behavior is to curl into a tight spiral, a defensive posture that makes them easy to identify.

It is helpful to differentiate millipedes from centipedes, which are also found in potting soil. Centipedes have flatter bodies, one pair of legs per body segment, and move much more quickly. Centipedes are predators, whereas millipedes are detritivores that primarily feed on decaying organic material within the soil, like old leaves and wood particles.

For a healthy houseplant, a few millipedes are not a cause for alarm, as they contribute to the nutrient cycle by breaking down waste. In small numbers, they are beneficial. However, a large infestation or scarce food sources may cause them to feed on the fine root hairs of plants or the tender tissues of young seedlings. This scenario highlights the need to manage their population if numbers become excessive.

Why Millipedes Are Attracted to Houseplants

The environment inside a houseplant pot is an ideal habitat for millipedes, drawing them in for moisture and food. Consistently damp soil is the most significant factor that attracts these arthropods, as they require a moist environment to survive. Overwatering, poor drainage, or a pot that is too large for the plant can lead to soil that stays wet, creating perfect conditions.

The composition of the potting mix also provides a food source. Most potting soils are rich in organic materials like peat moss, compost, and shredded bark, which are the primary diet for millipedes. The presence of leaf litter or other organic debris on the soil surface further enriches their habitat, making the pot an inviting place to live.

How to Get Rid of Millipedes in Houseplants

If millipede populations become too large, the most straightforward approach is manual removal. As you see them on the soil surface, scoop them out. They are slow-moving, especially after watering, and can be easily collected and relocated outdoors.

A simple trapping method uses a piece of raw potato or apple. Place a slice on the soil surface in the evening. Nocturnal millipedes will be attracted to the moisture and food overnight. In the morning, lift the slice and the millipedes gathered on it, and dispose of it.

A soil drench using an insecticidal soap and water solution can also be effective. This mixture breaks down the millipede’s exoskeleton, causing them to dehydrate. Mix the soap according to the product’s instructions and thoroughly water the plant, allowing the solution to flush through the soil and drainage holes.

The most thorough method is to repot the plant entirely. Gently remove the plant from its pot and shake off as much of the old soil from the roots as possible. Rinse the roots under lukewarm water to dislodge any remaining soil and millipedes, then replant in a clean pot with fresh, sterile potting mix.

Preventing Future Infestations

Adjusting your plant care routine is the best way to prevent their return. The most impactful change is to modify your watering habits. Allow the top one to two inches of the soil to dry out completely between waterings.

Ensuring your pots have adequate drainage is also important. If a decorative pot lacks a drainage hole, use it as a cachepot for a plastic nursery pot that allows water to escape. Avoid letting plants sit in trays of standing water, as this contributes to saturated soil.

Regularly clear away fallen leaves or other organic debris from the soil surface to remove food sources and hiding spots. When you bring a new plant home, inspect the soil for pests. Using a high-quality, sterile potting mix for repotting also reduces the chance of introducing millipedes from a contaminated source.