Skip to Content

Warm Season Grass vs. Cool Season Grass - How To Choose

A Legacy™ Buffalo Grass Lawn In Boise, Idaho
A Legacy™ Buffalo Grass Lawn In Boise, Idaho

By David Salman, Chief Horticulturist

Planting A Waterwise Lawn From Seed and Plugs

Many homeowners are in the process of making the decision to convert their lawn to more waterwise, low-care turf grass varieties. This will be a wise choice for both their pocketbooks and the environment. When installing a lawn, unlike rolling out high-water sod, the low water/low-care lawn grass options are usually planted from seed or plugs (small rooted plants). Hence, the timing and methods used to establish a new lawn are different than when laying sod. Here are some considerations about grass types and the timing of planting to help homeowners make the right choices to get their new lawn established.

Cool Season and Warm Season Lawn Grasses Defined

The first decision to be made is to choose the best type of grass for your use and your region's climate.

There are two basic types of grasses: warm season grasses and cool season grasses. This is important information as it relates to:

  1. When are they in active growth?
  2. When it is best to plant?
  3. When do they become green at the start of the growing season and when they go dormant in the fall?

Warm season grasses are varieties that are in active growth beginning in late spring and go dormant in early to mid-fall. So they "green-up" in late spring when the nights begin to warm and go brown in mid-fall (late Sept.-Oct.) These grasses are very intolerant of shade. The more sun the better.

Cool season grasses are varieties that are in active growth ("green up") much earlier in the growing season (mid-spring) and stay green longer into the fall before going dormant in late fall. But without regular summer watering, they will go dormant in the heat of summer. These grasses will tolerate a little shade but need at least a 1/2 to 3/4 of a day of full sun.

Considerations When Choosing Between Warm and Cool Season Grasses

  • For some homeowners, having a green lawn for as long as possible is of primary importance. So cool season lawn grasses will be their best choice. But the trade-off is that cool season grasses are not as water efficient as warm season grasses and will use noticeably more water than warm season grasses (but less than high-water Kentucky bluegrass).
  • For homeowners with properties at higher elevations (above 6 to 6,500 ft.) and more northern latitudes (Washington, northern Idaho, Montana, the Dakotas, Wisconsin, Minnesota, Michigan, New York, Vermont, New Hampshire and Maine), warm season grasses are not a good choice. Here, cool season varieties will perform best.
  • For homeowners who live in the lower latitudes of the US where summers are hot to very hot, warm season grasses are the best option. Cool season varieties will need a lot of water to keep them in active growth.

Best Practices For Planting Grasses

The planting season for warm and cool season grasses is somewhat different.

Warm Season Grasses - It is recommended that warm season grass plugs be planted after the last average frost date when night temperatures are consistently warmer. With adequate watering, plugs will establish their roots more quickly, stay actively growing and fill in rapidly.

  • Planting too early when there is still danger of frost and nights are cold will keep warm season grasses dormant, delay active growth, and give the weeds (many of which are cool season growers) a big head start. 
  • Summer is an excellent time to plant warm season grasses! Just be sure irrigation is in place to keep them moist as they establish and grow.
  • At the end of the growing season, warm season grass plugs should be planted at least 8 weeks before the first average frost date of fall.

Cool Season Grasses - These grasses are usually grown from seed (with the exception of Bluegrass 'Bella') and germinate well when the nights are cool. Spring sowing of seed can begin in mid-spring before the last average frost date of spring and continue until early summer. 

  • Sowing cool season grass seed in summer when temperatures are in the 90's and triple digits is discouraged. It's too difficult to maintain optimum moisture for germination and young seedlings. 
  • For fall in colder and more northerly areas (zones 3-4), planting 'Bella' plugs should be done 6 to 8 weeks before the first frost. In zones 5-7, where fall is longer and cold temperatures don't arrive until later, early to mid-fall, provides an excellent window during which to sow cool season grass seed and plugs.

Learn More: How To Plant Native Grass Seed Mixes 

Grass Plugs - Superior Warm Season Grass Varieties

There have been many improvements made to turf-type lawn grasses to give homeowners much better options than were traditionally available 15 to 20 years ago. Now the best lawn-type warm season grasses like Dog Tuff™, and buffalo grass varieties like Legacy™UC Verde™ and Prestige™ are grown from cuttings rooted into plugs.

Learn More: About Buffalo Grass Plugs: Summer Is Time To Establish Native Grass Lawns

Learn More: Customer Success: Planting Dog Tuff Grass Plugs

Need More Guidance?

View our lawn chart with important grass characteristics and timing of planting. 

Contact us to learn more! Request A Free Sustainable Lawn Consulation


Shop Sustainable Lawns