The late, great Spike Milligan once wrote “Today I saw a little worm wriggling on his belly, perhaps he’d like to come inside and see what’s on the telly”. There’s no denying that, for gardeners, worms can be as divisive as Marmite. Before you start to worry about worms in your lawn though, let’s not overreact and feel like we have to eradicate them altogether.
Earthworms are not necessarily bad for our lawns as they are an important part of the eco-system. It’s fair to say the ‘pros’ outweigh the ‘cons’ when it comes to worms, as they recycle nutrients, feed on dead plant material and create natural aeration in the soil. That said, worm casts produced on the surface of our lawns (usually between autumn and early spring) can be a real irritation. The casts can cause turf surfaces to become muddy, slippery, unsightly and can create loads of potential ‘weed pockets’ with each cast.
There are numerous types of earthworms in the UK, but only a few varieties create worm casts. Casting worms eat the soil, digesting and extracting the goodness from it as it passes through their bodies. The casts, which are pushed up as they work through the soil, are the by-product of this process.
Here are our top tips on how to control worm cast damage to your lawn:
- Keep your lawn free of fallen leaves. If they are left to decay, they will provide a rich food source for the worms. A rotary lawn mower, garden vacuum, leaf blower or leaf rake will all do the trick. Click here for our really useful guide to clearing leaves.
- Remove grass cuttings. If they are left to decay, they too will provide a food source for the worms. Either collect your cuttings as you go, or opt for a more high tech solution like a robotic mower which mows daily so clippings don’t accumulate.
- A worm cast control product can be applied in late September/October. These products do not kill the worms but act as an irritant in the surface layer, encouraging the worms to go deeper into the soil and therefore produce fewer casts. These products should only be applied by a licenced lawn care professional. Update – From 2017 chemical worm cast control will no longer be available in the UK
- If your lawn is dry enough, a stiff broom or rake can be used to flick the casts away from the lawn.