What did you seed with? What was there before?

 

Lesco TTTF blue tag seed. Didn’t notice this before as I killed my entire lawn and leveled it with screened topsoil and the used mix of compost (leafgro and mushroom) to cover seeds. He’s a link to my journal that has some pics Pbear38 Lawn Journey (7B)

 

If the compost didn’t “cook” at high enough temp or long enough who knows what was in there. Let them grow a little and see what happens, not that there is much you can do right now.

 

This looks like roots from a nearby tree or bush that have grown to the surface.

I am currently observing this on a fallow area that has been covered with a sheet for a long time:

However, these roots are white and probably come from hornbeams standing nearby.