There are 28 species of worms in the UK. Only 3 produce casts that can cause a negative impact on the aesthetic qualities of a turf surface, producing casts in the spring and autumn periods.
A worms principal food source is dead or decaying plant material and thus they play an important role in the incorporation of organic matter into the soil.
Worms come to the surface in heavy rain to avoid drowning. If they can’t move back into the soil and are exposed to the sun they will die.
Earthworms perform a lot of positive activity, about 90% of autumn leaves may be pulled down into the soil and as such the depth of top soil can increase. Earthworms and their burrows also play a role in aerating the soil and aid drainage as a result.
The problems of worm casts can be reduced in a number of ways, firstly if the grass is cut at the right height approximately 1-1.5 inches or 25 – 37mm then casts will be less evident visually.
