The Rockdale Gardener

Gardening Posts From Rockdale Cooperative Extension

Little mounds of soil in turf; probably earthworm castings

by Steve Pettis, Rockdale Extension Agent with contributions from Wade Hutcheson, Spalding County Extension Agent and Paul Pugliese, Bartow County Extension Agent

Earthworms consume soil, extract the nutrients and excrete the waste as tiny soil pellets on the soil surface.

Earthworm_uga urban ag center

Earthworms consume soil, digest nutrients and excrete the remainder as pellets called castings.

Extension agents have had several clients come in with pictures of earthworm infestations in turf. They have large numbers of the mounds of castings in their lawns; sometimes whole yards are covered and the castings are an inch deep. One client in Rockdale County has a whole acre full of the worms!
earthworm castings

Earthworm castings can reach epidemic proportions in lawns. Fortunately these mounds are merely a nuisance and do not harm the turf.

It seems that the enjoyable fall weather and soil moisture has made the underground worms very happy as they do seem to be everywhere in some lawns. There is no reason to be concerned however since these animals are beneficial to the environment as recyclers. The worst thing that might happen is that the worms over-aerate the turf causing it to dry.

However, there are creatures out there that can kill turf. If you are concerned that your grass is being damaged by something, you might want to look for grubs. Grubs are the white, c-shaped larvae of beetles. These baby insects eat grass roots killing turf. To check for the grubs you can dig up some turf and look for grubs beneath…don’t consider treating unless you find eight-ten grubs per square foot.
The appearance of the castings can be annoying. The good news is that the castings will ‘melt’ with next rain fall or you can rake or sweep them into the turf. You are also getting ‘free’ nutrients from the worms for your grass.

The c-shaped larvae of beetles (white grubs) live in the soil and eat grass roots. If you find more than 8 per square foot, you might consider treating the insects.