Use a slow-release fertilizer, and avoid putting down more fertilizer than you need. Adding too much nitrogen can cause rapid growth and a thinning of plant cell walls, which makes grass more susceptible to disease. The excess fertilizer may also leach and eventually find its way into waterways, polluting them.
When restoring a lawn, apply the fertilizer as recommended by the results of your soil test.
If you did not test your soil, apply a slow-release fertilizer with a nitrogen-phosphorus-potassium ratio of 3-1-2. Apply about ½-pound of nitrogen per 1,000 square feet of lawn. It is best to apply fertilizer at least a week prior to spreading seed. Water the fertilizer into the soil if it does not rain before seeding.
REMEMBER: you shouldn’t feed a stressed lawn—adding nutrients without knowing what nutrients are required is like taking medicine when you don’t know what’s wrong.