To seed a new lawn, perform a soil test, and amend the soil as recommended. Till, or manually loosen, the soil to a depth of 3 inches, rake over the soil to ensure it is loose, and smooth the soil surface. Apply fertilizer, topsoil and compost to the lawn, work the materials into the soil, and broadcast the grass seed in perpendicularly-placed rows. Rake the soil lightly, and spread the grass seed again, then water the lawn thoroughly.
Choose a type of grass, or grass seed mix, that is recommended for the climate in the region, and apply the seed according to the instructions on the seed packaging. When broadcasting grass seed, use a weighted seed spreader to sow the seeds in straight rows, then broadcast the seeds at a perpendicular angle to the first set of rows to ensure even coverage.
Rake the soil to lightly cover the first application of grass seed, and follow the broadcasting procedure a second time. Maintain a frequent watering schedule until the grass develops hardy roots.
To seed an existing lawn, remove weeds with a nonselective herbicide, and wait for 10 to 14 days to apply the seeds. After broadcasting the seeds, apply a layer of mulch, compost or peat moss to the area. Avoid mowing the lawn until the grass is well-established.