septic tank - no grass!!

[B&H]

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

[Brad]

I've seen this problem with a few of my neighbors. I think the tops of their tanks are just too shallow and there isn't enough dirt underneath the grass to retain the proper moisture and nutrients.

[default]

That was my immediate reaction, too: The soil over the tank is too sandy, shallow, and drains too well to easily support grass.. Get a trailer load of straw, rotted leaves and/or seaweed, and till that in.