COOL & WARM SEASON GRASSES
Turfgrasses are categorized as either cool season or warm season, according to their optimum growth periods. Cool season grasses grow actively in the cool weather of spring and fall and somewhat slower in the heat of summer. Optimum growth temperatures range from 60-75º F. Warm season grasses grow vigorously in the summer months. The optimum growth temperature range for warm season grasses is 80-95º F. Warm season grasses will lose their color when soil temperatures fall below 50º F and will go dormant after the first frost in the fall. Full turf establishment for both cool season and warm season grasses will take two to four months.
The cool season grasses do best in the Cool Humid and Cool Arid Zones of the U.S. There are differences in cold hardiness of cool season grass species; bluegrasses, fine fescues, and bentgrasses are more tolerant of harsh winters than perennial ryegrass and tall fescues. Tall fescues have better heat tolerance than the other cool season species and are better for establishment in the southern regions, as well as in the upper portion of the Warm Humid Zone. Planting cool season grasses in late summer or fall will offer better competition against weeds and summer diseases.
Here is a list of cool season grasses with recommended planting time by zone:
Species
Zone
Planting dates
Bentgrass
Cool Humid, Cool Arid
August 1 to September 15
Bluegrass
Cool Humid, Cool Arid
August 1 to September 15
Fine Fescue
Cool Humid, Cool Arid
August 1 to September 30
Perennial Ryegrass
Cool Humid, Cool Arid
August 15 to September 30
Annual Ryegrass
Cool Humid, Cool Arid
August 15 to September 30
Tall Fescue
Cool Humid, Cool Arid, Warm Humid
August 15 to September 30
The warm season grasses do best in the Warm Humid, Warm Arid, and Subtropical Zones. Many warm season grasses do not produce viable seed and must be established with sod or sprigs. Warm season grasses are generally more aggressive and tolerant of drought and heat stress. Warm season grasses are very wear and traffic tolerant. Modern turfgrass breeders have developed new varieties of Bermudagrass and Zoysia that show increased cold tolerance. Warm season grasses such as paspalum also have excellent salt tolerance.
Here is a list of warm season grasses (with seed available) with recommended planting time by zone:
Species
Zone
Planting dates
Bermudagrass
Warm Humid, Warm Arid, Subtropical
April 15 to July 15
Bahiagrass
Warm Humid, Subtropical
April 15 to June 30
Zoysiagrass
Warm Humid, Warm Arid
April 15 to June 30
Centipedegrass
Warm Humid, Warm Arid
May 1 to July 15
Carpetgrass
Warm Humid, Warm Arid
May 1 to July 15
Buffalograss
Warm Humid, Warm Arid
April 15 to June 30
Paspalum
Warm Humid, Subtropical
May 1 to July 15