Knobbly lawn problem
By Arbuthnot
Buckinghamshire,
United Kingdom 
Our small back lawn is full of hard knobbles, roughly half an inch in diameter. They are very uncomfortable to walk on and are not visible. I thought they come from the roots of two huge trees (cherry and goat willow) in the next door garden but on digging down a little could find nothing. Can anyone say what they might be and give some advice please? A neighbour suggested anthills and while each summer I regularly put down ant powder there is no sign of them when I dig down.
4 Jun, 2022
Answers
I don’t see how a picture would help, Owd, as the knobbles are totally invisible. You only know they’re there when you step on one.
No, beech trees that I’m aware of. I do have a sambucus and there was an ash tree close to the fence on the other side but that was chopped down a few years ago.
4 Jun, 2022
Can you dig up one of these knobbly things?
In ours the knobbly things are either Beech nut cases or bits of tarmac from the old drive.
4 Jun, 2022
I’ll have a go but when I tried to dig down yesterday there seemed to be nothing there. Watch this space!
4 Jun, 2022
Odd.
Dried out worm casts? They can be pretty solid.
4 Jun, 2022
I dug down under two. One was just a small clump of matted grass roots, the other contained small pieces of sandstone. This estate was built on the site of an old brickworks so now I’m wondering if the dry weather we keep getting is the cause of it. Every time I dig in a flower bed I come across dozens of stones of varying sizes and it seems that when it rains they all come to the surface. On the lawn they can’t. I don’t think we’re prepared to get a new lawn though.
If anyone else has any solutions please let me know.
4 Jun, 2022
Picture would help if possible.
And are there any Beech trees nearby?
4 Jun, 2022