Earthworms

Eathworms are an important part of the garden ecosystem and benefit the lawn by increasing fertility and aeration. Earthworms vary in size and colour, with almost 30 species in the UK, and all help create good soil structure. 

Earthworms occur in most soils, unless there are issues with drainage or acidity. They feed on decaying plant matter, so do not cause damage to healthy, growing grass. Earthworms are less active during hot and cold weather. Some species come to the surface in search of dead leaves and similar debris which they may pull into their tunnels. A few species live permanently underground, and it is these earthworms that create the worm casts that can cause problems for the lawn. 

The worm casts are made up of soil that has passed through the digestive tract of the earthworm. Aside from being a potential eyesore, the worm casts may be flattened when mowing the lawn which creates a uneven, muddy patches. These patches impact the growth of finer grasses which become covered with the muddy soil, but are ideal for the growth of weeds.

 The worm casts should be tolerated as far as possible as the earthworms are an important part of a healthy ecosystem. The casts can be managed by brushing off when dry. Removing grass clippings and dead leaves will also help with management of worm casts on the lawn. In extreme cases professional help may be required, but given the benefits earthworms bring to soil structure and fertility it is far better to manage the situation as part of good lawncare.