Millipedes are often overlooked, but they play an important role in a healthy garden. These slow-moving members of the class Diplopoda feed mainly on decaying leaves, dead plant material and other organic matter. As they feed, they break larger pieces of debris into smaller fragments, making them easier for fungi and bacteria to decompose.
This activity helps return nutrients to the soil and supports the natural recycling of organic matter. Millipedes are not the same as centipedes: they generally feed on decaying material rather than hunting other animals. Understanding their habits can help you recognise when they are beneficial garden residents and when their numbers may become a problem.
Written by Kutlwano Mokoena
Founder of Evergreen Hideout. Focused on soil life, garden ecology and the organisms involved in natural decomposition.
Quick Summary: Why Millipedes Matter
Most millipedes feed on dead leaves and decaying plant material, breaking it into smaller pieces that support further decomposition.
Many species curl into a protective coil when disturbed. Some also release defensive chemicals from glands along their bodies.
Millipede Anatomy and Movement
Millipedes have long, segmented bodies with many short legs. Their name comes from the Latin roots meaning "thousand feet", although no millipede species actually has a thousand legs. Most body segments have two pairs of legs, a feature associated with the fusion of two segments during development. These fused sections are known as diplosegments.
Their many legs move in coordinated waves, helping them travel through leaf litter, loose soil and decomposing plant material. Unlike centipedes, which are adapted for fast movement and hunting, millipedes usually move slowly as they search for food and shelter.
Many millipedes also have a firm outer covering that helps protect their bodies. Some species can curl into a tight spiral when disturbed. This behaviour, called volvation, helps shield the softer underside and vulnerable legs from potential predators.
How Millipedes Help Recycle Nutrients
One of the most useful things millipedes do in a garden is break down dead plant material. They feed on fallen leaves, rotting wood and other decaying organic matter. Their feeding and movement fragment this material into smaller pieces.
After digestion, millipedes leave behind droppings, often called faecal pellets. These contain partially digested organic material and nutrients. Soil fungi, bacteria and other decomposers continue breaking down the material, helping nutrients return to the soil.
This process contributes to the natural formation of soil organic matter. Millipedes do not create finished compost on their own, but they are part of the wider soil food web that helps turn plant waste into material that supports soil fertility.
In gardens with leaf litter, compost and organic mulch, millipedes can be useful members of the decomposition community. Their presence often indicates that suitable food and moist hiding places are available.
Millipedes vs. Centipedes: How to Tell Them Apart
Millipedes and centipedes are both many-legged arthropods, but they have different body structures, behaviours and feeding habits. Knowing the difference can help you understand what you have found in your garden.
- Millipedes: Usually have rounded or cylindrical bodies, two pairs of legs on most body segments, and a slow-moving gait. Most feed on decaying plant material.
- Centipedes: Usually have flatter bodies, one pair of legs per body segment, and move more quickly. They are predators that feed on insects and other small animals.
Centipedes have modified front legs called forcipules, which they use to inject venom into prey. Millipedes do not have these venom-injecting structures. Instead, many species rely on their tough outer covering, curling behaviour or chemical secretions for defence.
Both groups have a place in the garden ecosystem. Millipedes help process dead organic matter, while centipedes help regulate populations of small invertebrates.
Frequently Asked Questions
Q: Why are millipedes eating my young seedlings?
A: Most millipedes prefer decaying plant material, but some species may feed on soft, living plant tissue, including young seedlings. This can happen when seedlings are tender or when conditions encourage large numbers of millipedes to gather in one area. Check for feeding damage at night, when many species are more active. Removing excess decaying material directly around vulnerable seedlings and protecting young plants can help reduce damage.
Q: Are millipede chemical secretions dangerous?
A: Some millipedes release defensive chemicals when handled or threatened. Depending on the species, these substances may cause skin irritation, discolouration or discomfort if they reach the eyes or mouth. Avoid handling unfamiliar millipedes with bare hands, and wash your hands thoroughly if you come into contact with one. Keep them away from children and pets.
Q: Should I remove millipedes from my garden?
A: Not necessarily. Most millipedes are useful decomposers and do not harm healthy plants. If you notice damage to seedlings, first check whether millipedes are responsible. You can reduce hiding places immediately around vulnerable plants, remove heavily damaged seedlings and use simple physical protection while the plants establish.
Q: Why do millipedes appear in large numbers after rain?
A: Millipedes need moist conditions to avoid drying out. After rain, damp soil and wet leaf litter can create favourable conditions for movement and feeding. Some may also move into buildings or other exposed areas when their usual hiding places become unsuitable.
Conclusion: Small Organisms, Important Soil Work
Millipedes may not attract much attention, but they contribute to the everyday work of a healthy garden. By feeding on dead leaves and other decaying material, they help break down organic matter and support the organisms responsible for further decomposition.
They are not pests by default, and their presence is often part of a functioning soil ecosystem. The important thing is to recognise their role, monitor any damage to young plants and manage the garden in a way that supports beneficial soil life without allowing local problems to develop.