"GaryM" wrote in message
. 3.44...
I have noticed that the grass over my septic system yellows and dries
in a perfect outline of the tank itself. Google searches have
explained why this usually happens. I was wondering if it is possible
to dig the soil out from over the tank, cover the top with an
insulation, say polystyrene tiles or something, then replace the
soil?

Would this be detrimental to the tank in any way? I have about 6
inches of soil over the tank and the ky. blue grass fares worst, per
expectations. The p. rye and fine fescue seem to do better. I suppose
the other alternative is to over seed with this seed exclusively.

Thanks in advance for any advice.

Gary

The reason it's drying out is there isn't enough soil over it for the roots
of the grass to go deep and remain hydrated. The solution would be to add
more soil if you want grass to grow there well. Or, add enough soil to make
it a decorative planter berm ,or leave it alone and plant xeric plants.
Making the soil even more shallow there for it to dry out even faster will
only result in your grass going dead faster.