When your lawn dries out the mushrooms will disappear. Do not worry,
they are causing no harm.

MPost wrote:
Because this summer was so wet in my area, I've had a moderate problem with
mushrooms in my lawn. They mostly are golf ball-sized or smaller, but on
occasion I've gotten ones bigger than a baseball. The big question is, what
do I do about them? They generally survive my weekly mowings since when I
mow, I leave my grass rather tall. I've been going around popping the caps
off, but I don't know if that's just serving to spread the spores around
more. And, I'm assuming the right thing to do is to solve the underlying
problem with excess moisture in my grass, but how? The lawn in most other
respects seems to be doing fine.