To seed grass, it is essential to prepare the site in advance. Grass seed needs a fertile and clear site or it will not germinate properly. You will end up with an uneven lawn with gaps. Prepare the soil one day and plant the seed the next, if you know the weather will be nice on both days. Wind or rain will affect the dispersal of seed, so it's best to check the weather forecast. Seed grass in the spring or fall for best results.
Prepare the yard by removing rocks, branches and other debris. Grass seed needs to touch soil directly in order to take root.
Get rid of weeds, as they can cause problems when seeding grass. If there are too many to pull out by hand, spray an herbicide over the entire area. Do this a few weeks before seeding to ensure the seed is not affected.
Loosen the soil to add air pockets. Run a rototiller at least 4 inches into the ground. If there are any low spots, level them off with topsoil. Rake the yard until it's relatively smooth.
Add nutrients to the local soil. Adding 1 inch of sand and compost will improve fertility and drainage. Combine them into the soil with the rototiller.
Use a starter fertilizer containing a lot of phosphorus to boost the nutrients in your yard. Read the package for instructions on setting the broadcast spreader.
Spread grass seed with a hand or mechanical spreader. Choose the method that works best for your yard size. It is essential to evenly disperse the seed so there are no gaps or competition for nutrients.
Cover the seed with a thin layer of soil. Rake it with the back of a metal rake to move 1/8 inch on top of the seed. This will keep it in place and help it germinate faster.
Set a sprinkler to the oscillating setting for even disbursement of water. Let it run twice a day for 5 to 10 minute intervals. Keep up with this schedule for 10 days then reduce watering to once daily for 15 minutes. If your climate is very dry, water for 30 minutes instead.