Common garden centipedes fall into the same category of animals as insects and are classified as arthropods, but they have a lot more body parts and legs than insects and tend to live in different places. Gardens can benefit from having them around in moderate numbers, and when managed carefully, there's no need to try to rid your yard of these creatures.
Centipedes tend to be long and flat, with their legs toward the outside of the body. All centipedes have one pair of legs per body segment, usually around 30 legs. They are fast-moving creatures, and will quickly scurry away when disturbed. Most common garden centipedes are dark brown or black. Some animals commonly mistaken for centipedes include millipedes and symphylids. Millipedes are much rounder than centipedes and have many more legs, and symphylids are shorter, white, and have only 12 pairs of legs.
Centipede Lifestyle and Reproduction
Centipedes are nocturnal predators and need to have a moist place in which to live and hunt. They lay eggs in moist areas in the spring and summer. When the eggs hatch, the young look like small adults, and sometimes will stay in the area for several days. Because they are lone hunters, these little centipedes can only be found in numbers early in life before they have dispersed from the nest. So, if you see a group of them, it's likely a nest.
Centipedes in the Garden
During the day, centipedes typically stay in moist soil, compost piles and under rocks, logs and mulch, where hide from the light. They are venomous, and although most are too small to bite people, the larger ones can pierce the skin. The bite is similar to a bee sting, and can cause itching and swelling at the bite site. It's a good idea to warn your children not to play with them. Centipedes will hunt anything that they are big enough to eat, and will take beneficial insects as well as harmful garden insects.
Centipedes are usually not considered pests, but given the right conditions can reproduce like crazy, in which case there will be little centipedes everywhere. If control measures are called for, the most effective control is to remove debris and move mulch and compost piles away from the garden and house. To prevent them from coming inside the house, lay down a barrier of gravel between the house and any garden beds near it, or regularly turn the mulch near the house to dry it out.