Ground spider is the name that many people use for a large group of spiders. The scientific name for the family is Gnaphosidae. There are many species in this family. There are a few that are fairly common one is the Parson spider (Herpyllus ecclesiasticus). This is a blackish spider with white abdominal markings. It is about 13 mm.
Commonly found dwelling beneath rocks, logs and other objects on the ground, ground spiders rarely leave their homes except to hunt. These spiders are red or gray-brown in color and may be solid or striped. Ground spiders do not possess venom that is medically concerning to humans.
While these spiders do spin silk, they do not trap prey within their webs. Rather, ground spiders hunt and chase prey along the ground. Hunting typically occurs outside, but ground spiders may also be seen in homes when temperatures drop significantly as they try to escape the cold.
Ground spiders produce silk through the use of their spinnerets, which are shaped like barrels. These glands are often instrumental in identifying ground spiders.
Ground spiders are nocturnal hunters. They do not make webs to capture prey. They forage aggressively for insects. During the day, they hide under stones or logs. When they come inside of homes, they spend the day in dark, quiet places. People who are bitten by spiders often say that it happened when they picked up something that had been stored for a long time. Shoes in closets are good hiding places for spiders.
Preventing ground spiders and other hunting spiders starts with eliminating their food. Since these spiders eat insects that crawl, inspect the outside for insect entryways. Ground-level entrances should be closed. Check exterior doors to be sure they close properly. Replace any missing weather-stripping. Check basement windows and crawlspace vents for proper screens. Squares of plastic screen can prevent insects from using weep holes as entrances to the home.
Move firewood piles away from the house. Move mulch 6″ to 12″ away from the foundation. This will create a “dry zone” that insects (and spiders) will hesitate to cross.
In order to successfully control ground spiders, contact your local pest management professional.