The grading contractor or a landscaper does the seed and straw — the grass seed and straw mulch that covers the bare dirt around a newly set home so the pad does not wash away before grass takes.
Short answer: After setup the ground around the home is bare, graded dirt, and the first hard rain moves it. Seed and straw is the quick fix: seed spread over the disturbed ground and straw laid over it to hold moisture and soil until the grass comes up. Sod is the faster, costlier version. On a sloped site the county may require soil stabilization — silt fence, matting or seeding on a schedule — and on a steep one an engineer or a stormwater inspector may be involved. The grading contractor often includes it; a landscaper does the rest.
Reviewed by a manufactured home setup contractor and dealer.