Pillbugs and sowbugs are small insects about half an inch long, with dark gray or brown hard segmented bodies, and small legs. They are crustaceans and distant relatives of lobsters. Sowbugs and pillbugs feed at night and seek refuge during the day in dark, damp locations, such as under pots. Under normal conditions, they are not harmful to plants because they normally feed on decaying matter. When their population expands significantly, sowbugs and pillbugs will start to feed on roots and low hanging foliage of garden plants and seedlings. They can also invade homes through cracks in the foundation or open windows to become a nuisance in the house.