Cool-Season vs. Warm-Season Grass: Which One Is Your Lawn?
Every lawn calendar starts with one question: is your grass cool-season or warm-season? The two groups grow at opposite times of year, so the right week to seed or fertilize one is often the wrong week for the other.
The two groups
Cool-season grasses grow best when air temperatures are 60–75°F. They are green from early spring to late fall, slow down in summer heat, and can brown out in drought.
- Tall fescue
- Kentucky bluegrass
- Perennial ryegrass
- Fine fescues (creeping red, hard, chewings)
Warm-season grasses grow best at 80–95°F. They green up in late spring, thrive in summer, and turn tan and dormant after the first hard frost.
- Bermuda grass
- Zoysia
- St. Augustine
- Centipede
- Bahia
- Buffalo grass
Where each one grows
- North (roughly north of a line from Kansas City to Washington, D.C.): cool-season lawns, mostly Kentucky bluegrass, fine fescue and ryegrass mixes.
- South (Gulf Coast, Florida, Texas, the Desert Southwest): warm-season lawns. St. Augustine and centipede near the coast, Bermuda and zoysia almost everywhere.
- Transition zone (Virginia, North Carolina’s Piedmont, Tennessee, Kentucky, Missouri, Kansas, Oklahoma and nearby): both. Tall fescue is the most common lawn, with plenty of Bermuda and zoysia mixed in. Winters are too cold for the most southern grasses and summers too hot for bluegrass.
On LawnWeather, the ZIP code report picks a likely grass type for your location, and you can switch between the two calendars with one tap.
How to tell what you have
Look at the lawn in mid-winter:
- Still green or mostly green: cool-season.
- Tan, straw-colored and dormant after frost: warm-season.
Two exceptions: in frost-free areas such as South Florida, warm-season grass stays green all year, and many Southern lawns are overseeded with ryegrass for winter color.
Then look closer at the grass itself:
| Clue | Cool-season | Warm-season |
|---|---|---|
| How it spreads | Mostly clumps (fescue, ryegrass); bluegrass spreads by underground runners | Runners above ground (stolons) you can lift with your fingers, and often below ground too |
| Blade | Fescue: wide and coarse with visible ribs; bluegrass: a boat-shaped tip; ryegrass: shiny underside | Bermuda: fine and wiry; St. Augustine: wide, flat, with a rounded tip; zoysia: stiff and dense |
| Summer | Slows down, may go brown in drought | Grows fastest |
If you see thick runners creeping over sidewalk edges, it’s almost certainly Bermuda, zoysia or St. Augustine.
What changes with grass type
| Job | Cool-season | Warm-season |
|---|---|---|
| Crabgrass preventer | Early spring, soil reaching 50°F | Same (often earlier in the year because the South warms first) |
| Seeding | Late summer to early fall | Late spring to early summer, soil above 65°F |
| Main fertilizer | Fall | Late spring through summer |
| Winter weeds | Rarely needs a fall pre-emergent | Fall pre-emergent as soil drops below 70°F |
Mixed lawns, such as Bermuda creeping into fescue, are common in the transition zone. Follow the calendar for the grass you want to keep.