Lawn Fertilizer Schedule: When to Fertilize Cool-Season and Warm-Season Grass
Fertilizer works best when it lands just as the grass is ready to use it. Feed too early and you grow weeds; feed at the wrong season and you push tender growth into heat or frost. The right schedule depends almost entirely on whether your lawn is cool-season or warm-season grass.
Cool-season lawns (fescue, bluegrass, ryegrass)
Cool-season grass grows hardest in spring and fall and slows down in summer heat. Its most important meals come in fall.
| When | Soil cue | What to do |
|---|---|---|
| Late spring | Soil past 55°F, grass actively growing | One light feeding. Skip it if the lawn is already thick and green. |
| Summer | Soil above 75°F | Hold off. Heat-stressed grass can’t use much nitrogen. |
| Early fall | Soil falling below 70°F | Main feeding of the year. Pairs well with overseeding. |
| Late fall | Soil falling toward 45°F | Last feeding, while the grass is still green. Roots keep storing food for spring. |
The common mistake is a heavy feeding in early spring. It pushes top growth before the roots are ready and feeds crabgrass right as it sprouts. Put down crabgrass preventer in early spring and save the fertilizer for late spring.
Warm-season lawns (Bermuda, zoysia, St. Augustine, centipede)
Warm-season grass grows through the heat of summer and goes dormant in winter. Its feeding season runs from green-up to about six weeks before the first frost.
| When | Soil cue | What to do |
|---|---|---|
| Late winter to early spring | Soil below 65°F | Don’t fertilize yet. A crabgrass preventer may be due. |
| Late spring | Soil holding above 65°F, lawn fully green | First feeding of the year. |
| Summer | Active growth | Feed every 6 to 8 weeks (Bermuda can take more; centipede wants much less). |
| Late summer to fall | About 6 weeks before first frost | Last feeding. Later nitrogen can make the grass more prone to winter injury. |
Feeding a warm-season lawn while it is still half brown mainly feeds the winter weeds that are growing in it.
How much?
A typical application delivers about ½ to 1 pound of nitrogen per 1,000 square feet, and most lawns need 2 to 4 pounds per year in total. The fertilizer bag tells you how to set your spreader for that rate. Slow-release nitrogen spreads the feeding out and is more forgiving.
The other two numbers on the bag are phosphorus and potassium. A soil test, available inexpensively through your state’s cooperative extension office, tells you whether your lawn needs them. Several states restrict phosphorus on established lawns unless a soil test shows a need.
A few rules that apply to every lawn
- Sweep fertilizer off driveways and sidewalks back onto the lawn. What lands on pavement washes into storm drains.
- Don’t fertilize before heavy rain or on frozen or dormant grass.
- Water lightly afterward if the label calls for it, to move the granules into the soil.
- Follow the label. Product directions override any general schedule, including this one.
Your local dates
The ZIP code tool shows whether the fertilizer window is open for your lawn right now, and each city calendar lists typical feeding windows from ten years of NOAA weather data.