It's a good thing. Just some decaying wood under your lawn. It shows your soil is actively doing it's biological thing.

Get out your 5 iron and swing at them if they bother you. (grin) Other folks here use a sand wedge.

Thanks buddy! :) I'm relieved soo much!

FYI, tomorrow morning at 6am, I will be applying aerated compost tea.

Me, too. Would you like about a thousand mushrooms that look mutated?

No? Me neither.

They mostly show up in my garden beds (mulched with shredded oak), but I do get some in the grass. Fewer than I used to.

I'll betcha your construction crew buried some trash wood bits here and there. Mine sure did.

Today, the builder was putting soil across my house to the new house. While the small truck was leveling the ground back and forth, I saw about 4 ft of 2x4 came up and got buried again. LOL.

I do have a debris too in front. Actually, a big stone about 4" long in my estimate. It's about 4" deep. I knew about it when I was core aerating. I even tried with a screw driver and it sounded the same as when we are hitting a concrete with a screw driver.

Those contractors just want to finish the job. All of them don't care.

You're absolutely right, they sure don't care. I had a chunk of concrete buried that, when the landscaper pulled it to put in the patio, was 3' long by 18" wide. He had some interesting commentary on that one.

It explained why I couldn't grow grass very well on that one spot. I've pulled up nails (expected), plastic bags (huh?), and corroded drink cans from the gardening beds.

When they York raked (I think that's what you call it) they moved at 30 MPH. That's sure not enough to get anything out. Once they were gone and I owned the place, I evened out all the rough spots and reseeded those, plus pulled several thousand small to middlin' rocks.

I find a driver works best. I might try the sand wedge next time, thanks Iowa