How to deal with worm casts

How to deal with worm casts
    One problem you might encounter around this time of year – particular when the wet weather strikes – is the emergence of worm casts on your lawn.

As you might have guessed, these are created by earthworms, and look like small mounds of mud. To an extent, it actually is mud – although ultimately what you are seeing is effectively worm excrement.

Worms feed on the material of dead plants, ingesting soil in the process. Like all animals, they have to expel their waste in some way and this is normally done underground. However, a few species deposit their casts on the surface – breaking up the smooth, lush green carpet effect that so many of us aim to achieve when it comes to looking after our lawns.

But why else are they such a problem? If you are unfortunate enough to stand on one, it can result in it being spread across the surface of your lawn, creating areas that are susceptible to the establishment of moss and weeds.


One way to reduce your chances of experiencing this problem is to keep on top of clearing your lawn of fallen leaves. As the leaves rot, this will cause earthworms to spend longer on the surface of your lawn as they feed, thus increasing the chance of them 'casting'.

The Royal Horticultural Society also recommends that reducing the pH of your soil could have the desired effect, as earthworms as less abundant in soils of an acidic quality.

Products containing sulphur are suggested for this purpose, as they can achieve this without killing the worms.


If you'd rather deal with casts as and when they appear, then your best option could be to use a wire rake to break up and disperse the matter. That said, you can only do this when the casts are dry, as otherwise you will only make the problem worse.

Have the teeth of the rake facing upwards, and move the tool from side to side across the surface of your lawn.

Who'd have thought earthworms could cause such trouble?!

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