What homeowner doesn’t want a great-looking lawn? To take proper care of your turf, it helps to understand the type of grass you’re growing and mowing.

You might have heard of cool-season grasses and warm-season grasses. But what do those categories mean? Where do types of like Kentucky bluegrass and St. Augustine grass fit into those groups?

Knowing the differences between cool- and warm-season grasses can help you give your lawn the care it needs. Get ready to learn about the various kinds of cool-season and warm-season grasses, the pros and cons of growing each, and the best practices for maintaining them!

 

What Type of Grass Do I Have?

If you recently purchased a property and aren't sure what type of grass you have, you can narrow it down by geography. If you live in a northern, cooler climate, then you likely have a cool-season grass like Kentucky Bluegrass or Tall Fescue. If you're in a warm, southern climate, you likely have a warm-season grass like Zoysiagrass or Centipede Grass.

The following descriptions of both warm- and cool-season grasses can help you determine which type you have in your yard.

 

Cool-Season Grasses

A lush, green lawn might not be the first image you picture when someone starts talking about cool temperatures. But cool-season grasses get their name because they start growing when the soil temperature reaches about 40 to 45 degrees Fahrenheit. They reach their optimal growth at soil temperatures between 65 and 75 degrees.

This means that, in the United States, the peak growing seasons for cool-season grasses are spring and fall.

Cool-season grasses flourish in the northern parts of the country, where they’re most likely to enjoy their ideal temperatures:

• New England
• Great Lakes region
• Upper Midwest
• Upper Plains states
• Pacific Northwest

However, grasses that are more tolerant of heat fare well in what’s known as the transition zone, an area of the country that stretches from east to west between warm and cold states, along the line where Kansas and Oklahoma sit.

 

Types of Cool-Season Grasses

From species like Kentucky bluegrass that homeowners love to the ones like creeping bentgrass that golf course groundskeepers prefer, there are cool-season grasses to suit almost every kind of use.

COOL-SEASON GRASSES	Kentucky Bluegrass	Fine Fescues	Tall Fescue	Perennial Ryegrass	Creeping Bentgrass
Heat Tolerance:	Medium	Low	High	Medium	Low
Cold Tolerance:	Medium to High	Medium to High	Medium	Medium	Medium
Sun/Shade Tolerance:	Prefers Lots of Sun	Prefer Shade	Prefers Sun, Can Tolerate Shade	Prefers Lots of Sun	Prefers Sun, Can Tolerate Shade
Resistance to Wear:	High	Medium	High	High	High
Irrigation Needs:	Needs Well- Drained Soil	Need Well- Drained Soil	Needs Well- Drained Soil	Needs Lots of Water	Needs Frequent Watering
Additional Notes:	Spreads  Quickly	Low Maintenance	Low Maintenance	Grows Quickly from Seed	Used for Outdoor Activity Spaces - Not Suited for Home Lawns

 

How to Care for Cool-Season Grasses

Irrigation: Generally speaking, cool-season grasses need about 1” of water per week between late spring and early fall. This amount can vary due to all sorts of conditions, such as the amount of rainfall received or the type of soil on your property (clay soil holds moisture well and needs less frequent watering).

 

Fertilizing:  The best time to fertilize cool-season lawns is in fall, usually September, when they’re actively growing and can use the fertilizer to strengthen themselves before winter. Applying it at a rate of one pound of nitrogen per 1000 square feet is recommended.

Need more information about figuring out how much fertilizer to apply? Check out our Ultimate Fertilizer Guide!

 

Mowing: Cool-season grasses like Kentucky bluegrass and perennial ryegrass are best mowed at taller heights between 2½” and 3½”. True to its name, tall fescue can be left to grow even taller and mowed to a height between 3” and 4”. Creeping bentgrass should be mowed extremely short, about ½” because of its dense growth—another reason it’s preferred for professionally maintained grounds and not home lawns.

 

Warm-Season Grasses

If cool-season grasses are the ones that thrive in mild temperatures, then it’s pretty easy to guess the conditions in which warm-season grasses thrive.

Warm-season grasses begin growing at a soil temperature between 60 and 65 degrees Fahrenheit. They achieve their optimal growth when the temperature reaches a balmy 90 to 95 degrees.

This means that, in the United States, the peak growing season for warm-season grasses is summer, the warmest season of all.

Because of their temperature needs, these grasses are found most commonly in the southern parts of the country:

• States along the Gulf of Mexico
• States along the southern Atlantic coast
• Inland southeastern states
• Parts of southern California

Grasses that are hardier in the cold, such as bermudagrass and zoysiagrass, also do well in the transition zone.

 

Types of Warm-Season Grasses

Just like with cool-season grasses, you’ll find warm-season grasses suited to just about every kind of purpose, from decorative use in homeowner lawns to high-traffic use in parks.

WARM-SEASON GRASSES	Centipedegrass	Bermudagrass	Zoysiagrass	Bahiagrass	St. Augustine
Heat Tolerance:	High	High	High	High	High
Cold Tolerance:	Low to Medium	Medium	Medium	Low to Medium	Low to Medium
Sun/Shade Tolerance:	Prefers Sun, Can Tolerate Shade	Needs Lots of Sun	Prefers Sun, Can Tolerate Shade	Prefers Lots of Sun	Prefers Lots of Sun
Resistance to Wear:	Low	High	High	Low	Low
Irrigation Needs:	Needs Little Water	Needs Lots of Water, Lots of  Drainage	Needs Little Water	Needs Little Water	Needs Lots of Water, Lots of  Drainage
Additional Notes:	Low Maintenance; Grows Slowly	Popular Choice for Activity  Spaces	Low Maintenance	Low Maintenance; Sprouts Slowly	Grows in  Wide Variety of Soil Conditions

 

How to Care for Warm-Season Grasses

Irrigation: One of the reasons that warm-season grasses are so tolerant of warm, dry weather is that they develop deep roots that help them survive in such conditions.

As a result, warm-season grasses generally need less water than their cool-weather counterparts. Supplying about ½” to 1” of water per week during the active growing season is suggested, though this amount will vary depending on local conditions.

 

Fertilizing: For any type of grass, the best time to fertilize it is the start of its active growing season, or immediately before it. Warm-season grasses benefit most when fertilizer is applied in late spring or early summer.

Again, warm-season grasses tend to need less care than cool-season ones. In many cases, applying one-half pound of nitrogen per 1000 square feet will do, though you should perform a soil test to most accurately determine your lawn’s needs.

 

Mowing: Warm-season grasses grow best when mowed to shorter heights; for most of them, a mowing height between 1” and 2” works well.

St. Augustine grass can be allowed to grow taller and mowed to 2½”, while bermudagrass and zoysiagrass can tolerate shorter heights between ½” and 1” (though keeping bermudagrass and zoysiagrass between 1” and 1½” during the growing season is recommended for good health).

 

Grass Seed Blends and Mixtures

If you want to grow cool-season grass from seed, you might find the bags on the shelf labeled as grass seed mixtures or grass seed blends.

Be careful! Grass seed blends are not the same thing as grass seed mixtures.

Grass seed blends contain different varieties of the same species of grass. It might sound strange, but you can buy a 100% Kentucky bluegrass blend.

The carefully cultivated varieties inside the blend (or cultivars) have slight genetic differences. Compare it to a dog with brown fur and another dog of the same breed with grey fur—they’re both dogs, just with different traits.

In the case of a cool-season grass seed blend, the different cultivars might be bred for traits like resistance to different diseases. This gives your grass better odds of surviving no matter what conditions may come.

Grass seed mixtures are different. They contain different species of grass. A common mixture you’ll find is a mix of Kentucky bluegrass, tall fescue, and several fine fescues.

Mixtures are excellent for yards with several different growing conditions. If half of your yard gets a full day of sunlight and the other half spends most of the day in the shade, a seed mixture might be your best option.

You’ll notice that mixtures and blends are generally created with cool-season grass seeds. Warm-season grasses grow so robustly and quickly that each cultivar is usually planted and grown by itself as what’s called a monostand.

 

 

Is My Lawn Dead or Dormant?

Both cool and warm-season grasses experience periods when they’re not actively growing, also called dormancy. While they’re dormant, your lawn might look brown, thin, or patchy.

Cool-season grasses go dormant during the warmest months of summer and the coldest months of winter, while warm-season grasses go dormant during the cool stretch of time from late fall until early spring. Either type can go dormant during a heavy drought.

Although it can be hard to tell the difference between dormant grass and dead grass, one simple way to check is to tug quickly and gently on a handful of some of your brown grass. If it comes loose with very little force needed, it’s likely to be dead. Have a landscaping professional examine it for further recommendations.

If, however, it feels firm and can’t be pulled out easily, chances are that it’s dormant but perfectly healthy and will bounce back to green life once the prime growing season arrives.

And now that you know when the prime growing season is for the type of grass on your lawn and what you have to do to maintain it, you have the basic information you need to get your lawn greener and healthier than ever.

 

NEXT: 6 Tips for Easy Landscaping