Cool-Season vs. Warm-Season Grass: Which Type Belongs in Your Lawn?
Choosing between cool-season and warm-season grass is primarily a climate decision. Get it right and the lawn more or less manages itself for the basics. Get it wrong and you spend years fighting dormancy, disease, or poor color at the wrong times of year -- symptoms that look like maintenance.
Choosing between cool-season and warm-season grass is primarily a climate decision. Get it right and the lawn more or less manages itself for the basics. Get it wrong and you spend years fighting dormancy, disease, or poor color at the wrong times of year — symptoms that look like maintenance problems but are actually the result of a fundamentally mismatched plant.
The Fundamental Difference: Growth Temperature
Plants that evolved in cool temperate climates use C3 photosynthesis, which is most efficient at 60–75°F. Plants that evolved in tropical and subtropical climates use C4 photosynthesis, which is most efficient at 85–95°F. This biochemical difference determines everything about how each grass group behaves in your lawn.
Per NC State Extension:
- Cool-season grasses: optimal growth at 60–75°F; slow or dormant above 85°F or below 40°F
- Warm-season grasses: optimal growth at 80–95°F; dormant (brown) below 55°F; damaged by frost