Prepare the soil for growing your grass in mid to late summer. Till the ground until it is loose and workable, then amend with compost or peat moss, working it into the top 4 to 6 inches of soil.
Check the soil pH by taking a sample to your local nursery. Grass thrives best at 6.0 to 7.5 pH. If the soil is too acidic (a pH below 7.0), add ground limestone at a rate of 50 to 100 pounds of limestone for every 1,000 square feet of lawn. If the soil is too alkaline (a pH above 8.0), add sulfur at the rate of 20 pounds for every 1,000 square feet of lawn.
Rake the soil smooth and break up any clumps, smoothing out the surface and making it even. Fill in any low areas and rake down any mounds. Sprinkle phosphorous over the surface of the soil and rake into the top 3 inches at a rate of 50 pounds per 1,000 square feet. Phosphorous, which creates strong roots and healthy grass, is easier to work in early rather than waiting until after planting grass seed.
Choose a seed mix variety that will provide the right type of grass for your area and situation. You may need a variety specifically for shady areas or areas in full daily sun. Choose a dense variety that will hold up under heavy foot traffic such as play areas. Contact your local nursery to find out about the best varieties for your location.
Sow the grass seed in late summer or into early fall when the soil is still warm and weeds are not much of a problem. Using a hand-crank seed spreader, sow 1/4 of the seed across the entire area and then repeat three more times, sowing the seed across the entire area. Covers the area well with seed. Using a plastic or bamboo rake, rake the seed lightly into the soil surface.
Set the seed well into the soil by rolling an empty lawn roller over the entire surface of the ground. This ensures the seed has good contact with the soil so it can take root.
Water the freshly planted seeds with a fine mist of water every day to keep the soil moist. One the seeds have germinated or sprouted within a week or two, water more heavily and less frequently allowing an inch of water weekly, including rainfall and irrigation.
Mow the grass when it reaches about 3 inches tall and be sure the lawn mower blades are sharp. Dull blades cn pull the new grass out of the soil. Cut the grass to no less than 2 inches tall at the beginning.
Apply fertilizer after the first time you mow the grass and use a high nitrogen-based fertilizer such as 23-4-6. Use only half the recommended amount listed on the bag and water in well immediately after fertilizing. Fertilize about every two months and always water well afterward or allow the rain to soak it in.