Question
Hello,

The lawn above my septic's leaching (sp?) field has turned yellow.

It gets the same amounts of water,fertilizer and sun as the rest of my lawn and the rest of my lawn looks pretty good.

I took a spade to the area above the septic and found that I have @ 2.5 inches of loam sitting on sand.

Is the problem;

a) not enough loam causing a lack of water retention, or,
b) too much "fertilizer" ... what I apply plus what leaches from the septic system?

If it's a lack of loam, I'd like to truck in some additional loam, probably add an additional 4 inches (it'll compact to 2 inches).

My question is ... can I apply the additional loam over the existing grass and reseed?

Not sure what the problem is.

thanks

Answer
I think the problem is the shallow dept above a structure which radiates heat and possibly collects water (standing water = root death).

Improving rooting dept by 4" would be a very good way to solve it. you can cover dead turf with soil and reseed. If the grass green back up, you can also cut the turf into small tiles and put aside with about 1-2" of dirt on the roots. Then put topsoil down and replace the tiles. water well to establish the roots in the new soil (like sodding).

I suspect that the roots die from lack of water caused by shallow rooting (2") and high heat which develop over such structures (same happens to concrete areas which has been covered by soil and re-seeded).

If the area is very squishy when you walk on it, drainage can also be a problem.

Fertilizing 3-4 times per year should not be enough and there really should not be any great seepage from the tank (or you have another serious problem). If ammonia collects in great qualities above the tank the grass would definately die, but septic tanks should not normally leak such amounts.