CHAMPAIGN, Ill. — According to a University of Illinois Urbana-Champaign press release, jumping worms often are found in the leaf litter or mulch layer and once established they can damage lawns, plants, and gardens.
Illinois Extension forestry research specialist Chris Evans said, “As the worms feed, they alter the soil by increasing aggregate size, creating larger clumps with more space in between,” Evans says. “This is caused by their castings making up a higher and higher percentage of the soil.”
Over time, the soil begins to look like coffee grounds, stated the press release. Since this sign is delayed and the worm’s microscopic eggs can survive Illinois winters, gardeners may unknowingly have them or spread them.
Learn more about how to identify and report jumping worms using a fact sheet.