How much organic content to support grass?

Factual Questions
1

About 2 weeks ago, I had some derelict buildings on my land removed, and the building sites graded. This left bare, almost virginal sand with some clay content as the current soil. I want to plant grass as soon as I can, with trees being a project for the near future.

I’m not so concerned with the trees, because the roots will go deep, and there is plenty of water available for them, and presumably minerals and other stuff. It’s the grass that has me worried. How much organic content does there need to be to support grass?

I SWAG the area to be 3000 ft[sup]2[/sup]. I’m going to my neighbors and begging them for horse manure to spread on the area, which will be disked in very soon. Will manure be enough? Should I consider other chemicals to add?

My goal is decent grass, but definitely not golf course quality. The area will become a hobby orchard, so the grass is more ground cover than lawn.

2

Probably about 4%. I’d spread the compost/manure about 2 inches thick, and then roto-till it in about 6 inches deep or so.

3

Grasses can live in some of the worst soil on the planet, but the more organics you can get into the soil, the better. The horse manure is a good start. Better yet would be leaves, clippings and the like, all disked in. Each time you mow the area, the clippings will add to the soil.

Sow a goodly amount of fescue and see what happens.