The success of a seeded lawn depends on how the soil is prepared prior to laying the seed. If the soil is missing nutrients or has the wrong pH, the seed will not germinate properly, if at all. Weed control is also an important part of growing a successful lawn from seed. Treating the soil for weeds with a selective herbicide gives the seed a head start over the weeds.
Till the soil to a depth of 4 to 6 inches. Test the soil for nutrients and pH level. Test kits are available at a nursery or big box home and garden store. Amend the soil with limestone if the pH tests shows acidic soil. Amend with compost of the soil is not acidic enough. If the soil is missing nutrients, combine the specific nutrient-based fertilizer with the amendment. Till the amendments into the top 6 inches of soil.
Rake the lawn smooth. Be sure to remove all root balls, stones and other debris in the lawn.
Spray the entire yard with weed control that contains glyphosate. The herbicide does not leave active soil residue, so it will not hurt grass seedlings. Be sure to follow all instructions on the brand of weed control you choose.
Spread the grass seed with a seed spreader according to the instructions on the type of grass seed you purchased.
Cover the seed with a light coating of topsoil to help with germination. Water the seed according to the instructions on the seed bag. Most seed must be watered twice per day, until the seed becomes established. If you live in an area with watering restrictions, call the water company or zoning (whichever company is regulating water usage) and let them know you just seeded. Most areas with water restrictions allow excess watering for newly seeded lawns.