Noticed my septic tank in Pacific Northwest will not grow grass over it. I
dug out all the overlying dirt to investigate, but other than some chunky
rocks (not the cause of the bare area, but certainly not helping either) and
moist dirt directly atop the tank, I am at a loss.

Is it possible that the exhaust from the tank is noxious to the grass?
Seems odd to me b/c I thought plants thrived when exposed to such an
environment.

Thoughts on the cause and suggestions on what to do to get the grass growing
for once? Any special dirt treatment?
tia
bob