Chill Out: The Best Cool Season Grasses for Your Lawn
"Choosing the Perfect Cool Season Grass Variety"
The best cool-season grass for your lawn depends on several factors, including your region's climate and soil. You'll also want to consider how much shade your yard receives and how much traffic it gets.
In general, cool-season grasses are less susceptible to heat than warm-season grasses. However, some varieties can turn brown in high temperatures.
Kentucky Bluegrass
Kentucky bluegrass (Poa pratensis) is one of the most popular lawn grasses in the United States. It is a perennial, cool-season grass that grows best in various northern climates.
Kentucky bluegrass is adapted to soils with a pH between 6 and 7 as with other cool-season grasses. It also grows well in well-drained, fertile, and moist conditions.
It is a self-spreading, sod-forming grass that spreads via underground stems called rhizomes to form a dense turf. This aggressive growth habit allows Kentucky bluegrass to recuperate quickly from damage.
In addition to its ability to spread and heal, Kentucky bluegrass is highly resistant to disease. Its rhizomes accumulate carbohydrates during the growing season, and these carbohydrate reserves help to stimulate new shoot growth in the spring.
Grass seed mixtures that contain Kentucky bluegrass tend to have lower thatch levels than other lawn grasses, which makes it easier to control thatch with thatch treatments. Annual thatch treatment, beginning roughly two springs after planting, is important to keep thatch levels reasonable.
Kentucky bluegrass is a great choice for many homeowners, but it does require more work than other cool-season grasses. If you want cool-season grass that requires less maintenance, check out our alternative, Black Beauty Ultra, which combines fine, tall fescue with perennial ryegrass and Kentucky bluegrass for a beautiful, low-maintenance lawn.
Perennial Ryegrass
Perennial ryegrass grows best in coastal regions, where temperatures remain moderate throughout the year. It is also resistant to many common lawn diseases and is a great choice for overseeding winter-dormant bermudagrass lawns.
This cool-season grass is popular for sports fields, golf courses, and parks. It can grow well in both full sun and partial shade. It is also highly adaptable to soil types with low pH and acidity. Research has resulted in a wide range of new cultivars with enhanced stress tolerance, improved mowing quality, higher insect and disease resistance, better leaf texture, and higher shoot density.
The best time to plant perennial ryegrass is early fall in most areas when days are still warm and nights have dropped temperatures. These conditions allow the seeds to germinate rapidly and prevent them from being killed by the cold.
It is a good idea to grade the soil before sowing the seed. This will help reduce water use in the future. Ensuring the soil is well-draining and has a proper pH level is also important. Establishing and maintaining the desired turf can make it difficult if the soil requires being in optimum condition.
Tall Fescue
Tall fescue grows well in areas with moderate to high rainfall. Therefore, it is a good choice for lawns, especially in climates where heat and drought are common problems.
In addition, the grass is resistant to disease. This makes it a good option for homeowners looking to reduce the number of chemical applications in their landscapes.
Another advantage of this grass is its ability to tolerate soil pH changes. It can survive in various pH ranges, from 4.7 to 9.0.
It is also a good grass to use when planting a grass hay or pasture system. It is a perennial grass that will not choke out the other types of turfgrass.
Early fall is the best time to plant a new tall fescue lawn. This gives the seeds time to grow and develop roots before the hot summer weather kills them.
You can also seed a tall fescue lawn in the spring. However, it's a little riskier. Because seed germination is slower in spring, seedlings can be susceptible to Fusarium blight and other diseases.
To keep your tall fescue lawn thick, mow the grass regularly enough to allow it to stay at least 3 inches high. This is because taller grass has more chlorophyll to do photosynthesis.
Fine Fescue
Fine fescue is the grass that thrives in cool, northern climates. Its low mowing requirements make it a popular choice for lawns in homes and various landscapes.
It also has a low water requirement and is drought-resistant. This makes it a good choice for areas with a lot of shade or where it is not easy to mow.
Another benefit of Fine Fescue is that it grows well in rocky or sandy soils. However, these conditions should only persist briefly as they will cause problems.
If you are considering planting a new lawn, a fine fescue seed blend is ideal. These blends contain several fescue species, which have been specially adapted to grow in different climate zones.
The best time to plant fine fescue seed is in the fall. This gives the grass seed time to grow before the summer heat sets in.
Once your seeds have germinated, you may need to overseed them with more fine fescue grass seed and mow the area to achieve a full, healthy lawn. However, be careful not to over-water your lawn as this can cause the fescue seed to wither and die.
Maintenance Needs of Cool-Season Lawn Grasses
Cool-Season grasses are adapted to the cold temperatures found in the northern two-thirds of the United States and throughout the world's four-season climate zones. These grasses can also withstand summer heat but require different optimum growing conditions than warm-season grasses to thrive.
When air temperatures reach above 50 degrees Fahrenheit for long periods in the summer, cool-season grasses may struggle and go dormant. This is why you'll see the strongest growth of cool-season grasses in the spring and fall.
You'll need to ensure that your cool-season grasses get the proper water and fertilizer during this period. You can start by adjusting the irrigation schedule to avoid over-watering your lawn.
Once your lawn gets enough water, fertilizer, and weed control, your cool-season grass should be ready to grow in the spring. Mow your lawn regularly so it's at its optimal height for your specific grass variety, and be sure to leave any clippings to help your turf stay healthy in the winter.
Doing an annual aeration of your lawn in the fall is a good idea. This will remove thatch, the layer of dead roots and organic material that can suffocate your lawn and harbor pests and diseases. In addition, aeration will improve your lawn's quality and increase its ability to recover from damage.
Shade Tolerance Lawn Grasses
When choosing grass seed, choosing a mix that suits your climate and shade requirements is important. Many grass seed companies, including Scotts, Pennington, and Greenview, offer different shade-tolerant mixes for various conditions.
Cool-season grasses generally tolerate more shade than warm-season types but vary in tolerance. Some varieties may become dormant in the summer if they don't get enough sunlight, while others, such as Kentucky bluegrass and perennial ryegrass, can grow even in light shade.
Fine fescues (creeping red, Chewings, sheep, and hard), rough bluegrass (Poa trivialis), and tall fescues thrive in areas with less than four hours of direct sun daily. They also perform well under trees with dappled sunlight that filters through the leaves.
For best results, trim trees and shrubs to open their canopy and provide more light for your grass. This can help improve air circulation and reduce competition for water, nutrients, and light from the grass and tree roots.
The soil in shady areas becomes unbalanced quickly, creating a favorable environment for weeds and other unwanted lawn mosses to thrive. Therefore, it's crucial to restore the soil pH to a healthy level and to provide adequate drainage. This can be accomplished by aerating the soil and adding organic matter such as Pennington Fast Acting Lime to the lawn area when necessary.
Traffic Tolerance Lawn Grasses
Cool-season lawn grasses differ in their ability to withstand traffic and recover from injury. Some, such as perennial ryegrass and tall fescue, spread through underground stems called rhizomes that protect the underground growth and allow them to recover quickly from injuries.
This projected growth is a key factor in their ability to stand up to steady traffic and be used by children and pets. Fine fescues, on the other hand, grow in upright clumps and spread through vertical shoots rather than hidden rhizomes, making them less resistant to traffic and easier to get injured. This group is one of the least traffic-tolerant of the cool-season grasses and should be avoided if you plan to use your lawn for heavy foot traffic or lots of pet play.
By understanding the traffic tolerance of each grass species, you can choose a seed or seed mix that will give you the best possible results on your lawn. But, of course, you'll also need to consider the sun your lawn receives and how much maintenance you want to do.