Kentucky Bluegrass: Care For This Cool-Season Lawn Grass

What is Kentucky Bluegrass?

Kentucky bluegrass (Poa Pratensis) is one of the flagship cool-season grass types to plant across the northern regions as well as transition regions of the United States.

Its soft texture, distinctly rich color, and ability to rapidly recover from moderate foot traffic have made it a winner for lawns, athletic fields, pasture grass, and golf courses.

Region of AdaptationNorth and Intermediate
Winter HardinessExcellent
Heat ToleranceRelatively good
Drought ToleranceFair
Shade TolerancePoor to Fair
Soil pH5.8 to 7.0
Maintenance RequiredHigh
ColorMedium to dark green
Leaf TextureMedium
Mowing Height1.5 to 2.0
Wear ToleranceGood
Recuperative CapacityGood
Establishment MethodSod, seed
Growth RateMedium
Growth HabitKentucky bluegrass rhizomes

It’s important to note that the information above may vary between Kentucky Bluegrass seed varieties. 

For instance, some stains may have a higher or lower shade tolerance or germination rates.

There are also combinations of seeds that could provide you with the lawn profile you prefer.

At the end of this article, we review some of the more popular grass-type blends. We welcome your comments and input.

Choosing the Right Strain of Kentucky Bluegrass

choosing-right-strain-of-Kentucky-Bluegrass

As can be seen from the above information, Kentucky bluegrass flourishes in a wide range of conditions.

Because of Kentucky bluegrass’s application versatility, Kentucky Bluegrass is one of the most researched turf grasses, with 89 strains in testing, of which 33 are commercially available.

Only Tall Fescue (132) and Perennial Ryegrass (114) have more variants in evaluation.

Given the 33 commercially available strains of Kentucky bluegrass, there is a high probability that, given proper guidance, you could plant a Kentucky Bluegrass strain that works for your needs and environment.

Currently, the top-performing Kentucky Bluegrass seeds are produced by GO Seeds and Barenbrug.

Certain grass seed strains to consider are Starr, Bombay, Cloud, from GO Seeds; and Turf Blue HGT (Healthy Grass Technology), a mix that includes the high performing Barvette HGT from Barenbrug.

How to Care for Kentucky Bluegrass Lawns

Below reviews each care element so that you can get the most out of your Kentucky Bluegrass Lawn.

  • Soil
  • Fertilization
  • Irrigation
  • Mowing
  • Thatch
  • Diseases
  • Shade
  • Stress Tolerance

Soil

It is good practice to do an annual soil test before planting a new lawn.

Proper soil preparation is critical for a high-quality Kentucky bluegrass lawn.

Do not plant Kentucky bluegrass in shallow, compacted soils or areas where the pH is too high or too low as it does not grow well due to its shallow roots in these conditions.

Tilling a good quality of organic matter in (e.g., compost, peat, or Coconut Coir) before planting is one of the best soil improvement strategies.

For every 1,000 square feet, add three to six cubic yards of organic compost until it is eight to 12 inches deep from the soil surface.

Kentucky Bluegrass grows thrives in well-drained, moist, and fertile soils with a pH of 6.0 to 7.0.

Loam soil, a mixture of silt, sand, and clay is preferred, but not essential.

Adding peat moss or coconut coir increases both the water holding and aeration capacity of your ground.

Lastly, the optimal time to plant Kentucky bluegrass seed is in the late summer to early fall.

The soil temperatures in northern lawns when tend to be between 50-65 degrees F (10 to 18.5 degrees C).

Fertilization

fertilization-kentucky-bluegrass

Fertilizer application is dependent on the bluegrass seed used.

Smaller doses of nitrogen are better for the traditional types where high nitrogen levels enhance susceptibility to leaf spot infections.

For newer finer cultivars to look their best, this cool-season grass demands higher nitrogen levels than other cool-season grasses.

Stripe rust attacks these grasses in the early spring and fall when they have poor fertility.

Poor fertility in the newer grass seeds causes them to become dormant early in the fall and slow to green up in early spring.

Kentucky bluegrass turf will function well with about four pounds of nitrogen per 1,000 square feet per year.

Only two to three pounds of nitrogen per 1,000 square feet is required when leaving clippings on the lawn after a mow for a lush lawn.

Irrigation

Kentucky bluegrass is considered a high maintenance grass and generally needs more water to stay green than most turfgrasses.

Its recovery from dormancy is rapid, which Kentucky bluegrass enters into to survive an extended drought if not irrigated.

If allowed to go dormant, bluegrass is water-saving grass, but it will turn brown in color.

All summer, maintaining a dark green color will require approximately 1.5 inches of water per week during hot weather.

You may reduce that to one inch per week in the spring and the fall.

Watering in the morning is the best time to water your lawn to help prevent some diseases.

The goal is to wet the soil to a depth of six to 10 inches. A good soaking less often is better than daily wetting.

Tip: when the turf begins to turn a bluish cast or when walking across the lawn leaves lingering footprints, the lawn needs water.

Mowing

mowing-kentucky-bluegrass

Most online advice suggests Kentucky Bluegrass should be mowed to a  short to medium height approximately above 2-inches.

This contradicts the National Turfgrass Evaluation Program finding where new variants prefer cuts between 1.5 and 2-inches.

The dwarf or compact types perform much better at heights as low as 0.75-inch. Lower mowing heights have the risk of destroying your lawn grass.

Re-incorporate your clipping in the lawn saves up to 50 percent nitrogen addition.

Clippings do not add to a thatch problem, but over-fertilizing does.  

Thatch

Bluegrass is known for producing a lot of thatch. Kentucky bluegrass lawns should have thatch treatment as a priority.

Dethatching annually in spring or every other year, commencing roughly two springs after planting, is the key to reasonable thatch control.

Thatch increase will require more watering to avoid localized dry areas developing.

Kentucky bluegrass proliferates west of the Cascade region (i.e., west coast of US), attaining up to a two-inch thatch in the first three years after planting.

As time passes, thatch on the west coast regions becomes less of an impediment.

Common Diseases and Problems

common-diseases-and-problems-of-kentucky-bluegrass

Several physiological and environmental illnesses and diseases typically impact home lawns. The list below is just a teaser.

A future post will explain how to make your lawn disease resistant, the symptoms to look for, causes, and how to reduce their negative impact on lawn health.

Diseases

  • Rhizoctonia brown patch
  • Snow molds, Dollar Spot
  • Red Thread, Anthracnose
  • Leaf Spots
  • Pythium Blight or Greasy Spot
  • Necrotic ring spot and summer patch
  • Rusts

Problems

  • Moss
  • Algae
  • Mushrooms and other fungi
  • Slime molds
  • Miscellaneous injuries

Shade

Kentucky Bluegrass prefers full sun but will grow and tolerate light shade.

Because it isn’t as heat-resistant as tall fescue and other warm-season grasses, it doesn’t fare well in sweltering summers.

For this reason, many lawn owners combine bluegrass Kentucky and TTTF (Turf type tall fescue) lawn grasses.

Kentucky Bluegrass will thrive in partial shade and in locations where it receives strong sunlight for 4-6 hours during the day.

Stress Tolerance

Kentucky bluegrass can withstand the harshest winters found in the Pacific Northwest.

Desiccation injury can occur in windy areas with no snow cover, although cold is rarely a concern for this grass.

Heat stress is uncommon in the Northwest, except the Tri-Cities and Medford areas.

We simply do not build the kind of heat load that would cause significant difficulties because the humidity is ordinarily low, and night temperatures are frigid.

Kentucky bluegrass is found east of the Cascades in every region.

In Central Washington, Kentucky bluegrass lawns that are 75 years old and still reasonably pure can be seen.

It’s unclear how well the newer cultivars will do in the long run.

This broad blade grass may be a substantial component for a longer time in combination with other species such as perennial ryegrass and hard fescue.

FAQs

Where does Kentucky bluegrass grow best?

Despite the fact that Kentucky bluegrass may be found across the United States, it is the most utilized grass type in the northern states, where it is best suited to temperatures that do not surpass 75 degrees Fahrenheit daily basis in July.

Why is Kentucky bluegrass so expensive?

When sown over a vast area, Kentucky bluegrass is a somewhat costly crop to be able to cover the entire plot of land. Kentucky bluegrass, despite the fact that it is a low-stature plant, needs feeding and watering to maintain its turf quality. Kentucky bluegrass germinates slowly and has a protracted juvenile stage, which is characteristic of the species. As a result, it takes time to become established.

How quickly does Kentucky bluegrass spread?

Kentucky Bluegrass seed germinates in as little as 14 days. As compared to other popular grasses it is much slower, for example, fescue and ryegrass normally sprout in 5–10 days. However, once it has grown, Kentucky Bluegrass spreads rapidly to cover a larger area of ground than other grasses.

Summary

Kentucky bluegrass will give as close to ideal turf as we can expect for east of the Cascades under ideal climatic conditions and with optimal fertilizer, water, regular thatch treatment, and timely implications of herbicides, insecticides, and fungicides.

Bluegrass produces a perfect lawn even with low upkeep. There are yet no cultivars that may be considered low-input turfgrasses.

With all of the study and breeding and selection work done on Kentucky bluegrass, it appears that we should have the greatest turfgrass at our disposal.

There is little doubt that we now have dozens of cultivars superior to older types, yet there are still several issues to address.

Other types of grass to consider

If you are looking for other varieties of grass to grow in your yard, check out our other related posts:

References

  • Miller, G. (2017). Kentucky Bluegrass. TurfFiles, North Carolina State Cooperative Extension.
  • Kentucky Bluegrass. University of Maryland Center for Environmental Science.
  • Kentucky Bluegrass. Central Oregon Agriculture Research and Extension Center, Oregon State University Extension Service.

About/Mentions: Kentucky Bluegrass, Lawn, Gardening, Sod

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