Send a sample of your soil to a soil laboratory to determine its composition. The lab will be able to analyze the sample and provide you with instructions for the type of fertilizer that will work best for your soil. You can find a laboratory through the phone book, Internet searches or by asking employees at home and garden centers. If you are unable to test your soil, ask neighbors which type of fertilizer works best in your area.
Using a handheld sprayer to apply fertilizer gives you control over the amount of fertilizer used, and it allows the fertilizer to be applied in an even manner. Use approximately 1 pound of fertilizer for every 150 square feet of ground.
Water the lawn immediately after applying fertilizer so that the water will keep the fertilizer and seed moist. New grass seed needs frequent water to encourage growth and good root structures.
Cover the fertilized seed with straw or mulch for protection. The cover allows for air to access the seed but keep moisture in the dirt so the seed does not get dry.
If you apply fertilizer too frequently, or in excess, the grass may suffer. Overfertilized seed grows too quickly, which can result in the development of a weak and insufficient root system.
Plant and fertilize when weather is mild, such as in the spring or fall. Fall is the optimal time to seed and fertilize as the new growth will have a long season to grow without exposure to the harsh and drying summer weather.