The best time to fertilize your lawn depends primarily on the type of grass you have (cool-season or warm-season) and the climate. For warm-season grasses (like Bermuda, Zoysia, centipede, St. Augustine), the ideal times are:
- Late spring (about two weeks after the grass turns green and breaks winter dormancy)
- Early summer (to help endure summer stress)
- Early fall (to recover from summer stresses and prepare for winter)
For cool-season grasses (like Kentucky bluegrass, perennial ryegrass, tall fescue), the best fertilizing periods are:
- Late summer into fall (to help recover from summer stress and promote root growth)
- Late spring (to boost growth before summer heat)
- Early fall applications also help prepare the grass for winter dormancy
It is generally advised to avoid fertilizing during the hottest part of the day or in extreme heat or drought conditions. The best time of day to apply fertilizer is late afternoon or early evening, and many recommend fertilizing a day or so after light rain when the soil is damp. In specific regional guidelines (e.g., Pennsylvania), cool-season lawns are fertilized 4 times a year roughly in early April, late May, mid-August, and mid-October, while warm-season lawns may need fertilizing only in late May and mid-July. Overall, fertilization during the growing season of your specific grass type, avoiding extremes of weather, and applying in the late afternoon or early evening are key for best results.
