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Lumpy lawn caused my worm casts

#1 · 2nd April 2023, 7:58 pm

Hi everyone.

I have a new lawn that was layed 2 years ago. It used to be nice a flat and easy to mow. Now, I have seen a lot of worm casts all over my soil and it's causing lumps of soil patches. This year my lawn is lumpy and it's difficult to use the lawn mower. Even when I walk over it, my feet sinks in a little. It appears the lawn has lifted higher from the ground by couple of inches.
In this situation, can I use a lawn roller to flatten the lawn even? Then perhaps aerate it after flattening to avoid compaction.
I have attached some photos that I've taken today after trimming the lawn.

Today, it's 2nd April 2023. I live in UK and it's getting little warmer now so I need to start doing something now to take care of the lawn.

If someone can advise me please.
Thanks in advanced.

Uploaded files:

#2 · 4th April 2023, 12:52 pm

Hi @nils

Thanks for getting in touch about your lawn niggles. It's a common question with lumpy bumpy lawns.

The first thing to note is that worm casts are a great sign of soil health. It means there's plenty of life in the soil. The big niggle is excessive worm casting which can be caused by ground that's too damp, so the worms are literally coming to the surface to prevent themselves from growing. This can happen on new build gardens or recently renovated ground where over time compaction or excessive hard core can mean that water pools in lawns and flower beds as a means of escape.

This may be why there are some settlement issues and lump and bumps also. Though saying that, the lawn looks in fair nick!

You could use a lawn roller to help smooth this out, but if there are issues around drainage, it will soon come back. I think what may be best for you is to mow it relatively short, say a setting 3 and then aerate the lawn with a hollow tine aerator. You can either buy a manual one or rent a powered one. Looking at the size of your lawn, a manual one would do this with half a day's effort. Then use the plugs that come out as a soil improver for the rest of the flower beds.

You can also use a fork but it's less effective.

If you do find really squelchy sodden ground its a sign that it needs proper drainage, which isn't a quick fix in most cases.

What I have done in this case with newly landscaped ground is find the lowest point of the lawn and then doing down by 2 ft and add some grit and organic matter as a mini soak away, often digging through a foot of clay to get there. It's hard work but stops you needing to completely lift the lawn.

But worm casts are a sign there is life and I'd aerate to hopefully sort the drainage and lumpy nature out.

Let us know how you get on!

Lee