When choosing a grass for your lawn, it is important to have a good understanding of warm season vs. cool season varieties so that you can make the best decision based on geographic location. While choosing a grass, it’s natural to want to make decisions based on aesthetics or maintenance preference, but selecting a variety that isn’t a good fit for the climate is sure to cause frustration and disappointment.
Hot, humid areas that experience temperatures between 80º and 95º F are best suited for warm season varieties. Zoysia, St. Augustine, bahia grass and centipede grass perform well in humid regions like the Southeast and Gulf while bermuda grass thrives in warm, arid climates. Warm season grasses go dormant in the winter when temperatures drop below 65º F; for this reason, many homeowners opt to overseed with cool season varieties to ensure that a beautiful lawn is achieved year-round.
Pictured above from left to right: zoysia grass, St. Augustine grass, bermuda grass, centipede grass and bahia grass.
For areas with temperatures that fall between 60º and 70º F, cool season varieties are best. Prime cool season locations are parts of the Midwest, the Pacific Northwest, and most of the Northeastern regions of the United States. Cool, humid weather is the perfect climate for cool season varieties to flourish. Grasses that are suited for cool weather include bluegrasses, ryegrasses and fescues. Unlike warm season varieties, cool season varieties do not go dormant in the winter.
Pictured above from left to right: bluegrass, ryegrass and tall fescue.
The transition zone is represented by a ribbon of “in-between” climates stretching across the midsection of the United States. In many ways, the transition zone is the most complicated area to select a grass variety because of the extreme temperature swings that occur throughout the year. The most common resolution to the transition zone dilemma is to grow warm season grasses during the summer months and to later overseed cool-season varieties as the fall and winter seasons approach.
The image below represents the USDA Plant Hardiness Zones. Look at the map below to determine which zone you are located in. This will help you decide if you need a cool season or warm season turfgrass variety.
Photo Credit: https://planthardiness.ars.usda.gov/PHZMWeb/
Additional Factors to Consider
Apart from understanding the difference between cool vs. warm season regions, it is also crucial to take into consideration humidity and aridity when choosing the grass that is best for your lawn. Warm/humid, warm/arid, cool/humid, cool/arid are the four zones observed in the United States. There are varieties best suited for each of these zones within the warm and cool season categories. In both warm and cool season varieties, traits such as tolerance, texture, disease resistance, maintenance requirements and fertility differ based on the breed you choose.
Where to Begin?
An understanding of warm vs. cool season varieties is the first step when it comes to choosing the right grass. However, as previously mentioned, there are so many more factors to consider beyond this distinction. We recommend browsing our various selection of premium grasses here. You can find character charts and regional maps under each individual sod variety we off so that you can make the best, educated decision for you. Be sure to also check out the article on How to Choose the Right Type of Sod. We are dedicated to going above and beyond in bringing you fine-tuned grasses designed to thrive in your backyard.
For more information, Sod University has also published articles on St. Augustine, bermuda grass, centipede and zoysia.