Cool-Season vs Warm-Season Grass: Which Do You Have?

Not all grass is the same. The type growing in your yard determines when it thrives, when it goes dormant, and how you should care for it. The biggest distinction is between cool-season and warm-season grasses.

Cool-Season Grasses

Common in the northern half of the US (and the transition zone). They grow most actively when air temperatures are between 60-75°Fand soil temperatures are 50-65°F.

• Kentucky Bluegrass — Dense, dark green, self-repairing via rhizomes. The most popular lawn grass in the north.
• Tall Fescue — Deep roots, drought-tolerant, handles shade well. Great for the transition zone.
• Perennial Ryegrass — Fast germination, fine texture. Often used for overseeding.

Peak growth:Spring (April-June) and fall (September-November). They slow down or go dormant in summer heat above 85°F.

Warm-Season Grasses

Common in the southern US. They thrive when air temperatures are between 80-95°Fand soil temperatures are 65°F+.

• Bermuda — Aggressive grower, full sun, very durable. Used on sports fields and lawns across the south.
• St. Augustine — Thick, carpet-like, tolerates shade. Popular in Florida and Gulf Coast.
• Zoysia — Slow-growing but forms a dense, weed-resistant mat. Tolerates some cold.
• Centipede — Low maintenance, slow-growing, prefers acidic soil. The "lazy man's grass."

Peak growth:Late spring through summer (May-September). They go dormant and turn brown when temperatures drop below 55°F.

How to Identify Your Grass

Look at your lawn in winter. If it stays green, you likely have a cool-season grass. If it turns brown, it's probably warm-season. For more precise identification, check the blade shape, growth habit, and color, or take a sample to your local extension office.

Why It Matters for Mowing

Knowing your grass type tells you when to mow (during active growth), how high to cut (warm-season grasses generally shorter), and when to fertilize and seed (soil temperature thresholds differ). Our Advanced Lawn Care tool adjusts all recommendations based on your grass type.