Kentucky bluegrass is one of the most popular grass types in American yards. Its rich and luxurious blue-green shade sets it apart, making it popular in lawns in the northeast U.S. Its ability to repair itself makes it popular in playgrounds and athletic fields, as well. When grown in the proper conditions, Kentucky bluegrass has a look like none other. It is a sod forming grass that’s often mixed with other grass types to develop more easily into sod.
Kentucky bluegrass is a cool season grass, and it has greater durability than other cool season grasses.
It grows best in the northern parts of the United States, and it is typically not found in the warmer south. It can withstand warmer, drought-prone weather, but it does so by going dormant. It’s strong enough that it will resume growing once the weather becomes more favorable.
Due to its cold tolerance, Kentucky bluegrass requires higher amounts of water to maintain a healthy appearance.
History of Kentucky Bluegrass
Despite what its name applies, Kentucky Bluegrass is not native to the United States. It received its name because its early application in the U.S. was as pasture grass in Kentucky.
As its popularity grew, the association stuck.
Today, it’s still found throughout the state of Kentucky, and can be seen on the rolling hills of the state’s landscape.
Kentucky bluegrass is native to Asia and Europe, growing in the cooler regions across the Eurasian steppe.
Its origin story within the United States is not entirely understood. The current theory is that European settlers brought it over as they arrived in the New World in the 1600’s.
It was used initially as a pasture grass, which it still is today. It has become a widespread, naturalized species throughout the United States. However, it is still considered a non-native grass type.
Why You Should Grow a Kentucky Bluegrass Lawn
Aside from its beautiful appearance, Kentucky bluegrass is also incredibly durable to high foot traffic and compacted soil.
It is found throughout the northern regions of the United States in lawns, parks, and athletic fields. It forms a dense mat-like sod in your yard, which allows it to fill in damaged areas quickly and efficiently.
You’ll never have to worry about bare spots in your yard that result from your kids playing or your dog digging.
It has a fine texture, in addition to its blue-green blades, making it feel soft as it forms a dense, thick mat across your lawn.
Because it grows quickly, Kentucky Blue maintains a uniform texture throughout yards that heightens its appearance. Additionally, it still has popularity as a pasture grass when grown to full heights and is notable for its popular taste among grazing livestock (though I haven’t heard this directly from any cows, sheep, or horses).
Special Water Requirements of Kentucky Bluegrass
Kentucky bluegrass grows short roots, so it requires extensive watering compared to other grass types.
This makes it susceptible to heat and drought, which contribute to Kentucky bluegrass’s inability to withstand the warmer, southern climates.
It is a true sod-forming grass, unlike fescues which are bunch-forming.
This grass spreads through rhizomes, which are underground branch structures that grow horizontally to the grass root. It forms lateral roots from which the new grass stems grow.
Different Cultivars of Kentucky Bluegrass
Kentucky bluegrass is one of the most commercially available grass types in the United States. Whether you’re growing your new lawn from seed, or laying sod in your yard, Kentucky Bluegrass is a good option for many homeowners (except in the south).
Its standard grass cultivar is widely available in any garden store, though improved grass cultivars are available from more specialized suppliers.
These are grown primarily for commercial use. However, many commercial grass suppliers also sell to the general populace, they just need to be contacted directly.
In this article I’ll share some information about the following Kentucky Bluegrass cultivars:
- Standard Kentucky Bluegrass
- Improved Kentucky Bluegrass
- Annual Bluegrass
Let’s take a look at these three options homeowners can consider for their bluegrass lawn:
Standard Kentucky Bluegrass
Standard Kentucky Bluegrass is the most commonly available variety.
They are generally low maintenance, compared to other cultivars of Kentucky bluegrass.
Special Issues & Concerns to Consider
Standard Kentucky Blue is prone to issues when over-fertilized because it makes this grass more disease-prone. If your yard is exclusively Kentucky bluegrass, then you can simply avoid using extensive fertilizers.
If your yard has a blend of grasses with common bluegrass as one of them, fertilizing regularly can become problematic since disease can spread from Kentucky bluegrass to the other grass types in your yard.
Improved Kentucky Bluegrass
The improved cultivars are typically only available for commercial use. These are used in professional athletic fields and are even more resistant to foot traffic than your standard Kentucky Blue.
Certain varieties make it easier to irrigate, and many are more tolerant of fertilizers and are faster growing/spreading.
Improved Kentucky Bluegrass for Shade
Rough bluegrass is a specific cultivar that has heightened shade tolerance. Unlike other varieties of Kentucky bluegrass, rough bluegrass does not grow well in full sun conditions, but it’s a good option for shady areas of your yard, or for lawns that are primarily in the shade.
Annual bluegrass is actually a grassy weed that has only a year-long life cycle. Its similarity to other types of bluegrass make it particularly deceptive, though it can be crowded out by maintaining healthy conditions for regular turfgrass and growing that turfgrass to about 3 to 4 inches in height.
Annual bluegrass is a “winter annual” that reaches maturity in the fall and lives through the winter. As it dies in the spring, it produces seed to grow its next year of plants.
It can hide among other lawn grasses and survive in athletic fields that are mown short.
You’ll notice it most in the late fall … because it grows when other grasses in your lawn are dormant.
The Best Time to Plant Kentucky Bluegrass
As a cool-season grass, Kentucky bluegrass grows best during the colder seasons of spring and fall.
It reaches its peak growth in weather between 50-degrees and 60-degrees Fahrenheit.
I recommend that you plant Kentucky Blue in the fall when the weather is consistently around that temperature, and when your seedlings won’t be competition with annual weeds that germinate each spring.
Kentucky Blue grows slowly during the summer months and will likely require a lot of additional water to maintain growth.
Due to Kentucky bluegrass’s increased tolerance for cold, it’s best to plant it during the fall. That allows the grass additional time to establish itself prior to the weather warming.
Preferred Growing Conditions
Kentucky bluegrass prefers full sun to grow best. It is not a shade tolerant grass type, though mixing it with other grasses can make up for that.
This variety of grass is also highly susceptible to drought due to its shallow root system. It does not grow the lengthy roots that fescues do, and that is why it cannot withstand the high heats of summer.
Those types of grasses are able to tap into water and nutrients deep underground. Kentucky bluegrass cannot do that and is reliant on the nutrients it can find at or near the surface of your lawn’s soil.
However, as newer cultivars are developed, new types of Kentucky bluegrass are being created that do allow for greater water tolerances.
Planting Kentucky Bluegrass
Kentucky bluegrass is widely available as seeds and will germinate quickly.
However, you should know that Kentucky Blue does take slightly longer to germinate than other cool season grasses. It’s also available to buy as sod due to its mat-forming tendencies.
Growing Kentucky bluegrass from seed is a fairly straightforward option and far more cost effective than sod or hydroseeding.
Growing your lawn from seed allows you to make use of grass mixes that will strengthen your lawn in other ways or optimize it for conditions that are tough on Kentucky bluegrass, like shaded areas (which virtually all lawns have).
Preparing Your Lawn
When seeding a new lawn, you want to first rake the ground to loosen the soil and remove debris.
Raking also creates grooves in the soil that will increase surface area to increase the seed’s contact with the soil. If your soil is compact, aerating your yard prior to spreading your seed is a great idea. This will provide numerous holes for the seed to penetrate, and improves the turf’s ability to absorb water.
Make sure not to use lawn weed killer or herbicide within a month prior to planting grass seed. Weed killers can either prevent grass seed from germinating or kill it as it takes root.
I always use a starter fertilizer when growing grass from seed, and my favorite is a Scott’s product which prevents crabgrass (but doesn’t interfere with grass seed germination. You can get it on Amazon, and sometimes you can find it locally.
It’s a quick-release product that gives your seedlings exactly what they need as they establish themselves in your lawn.
Once your lawn is prepared, it’s time to choose your grass seed.
You can purchase Kentucky Bluegrass seed at any home and garden store, as well as specialty stores and online at Amazon or elsewhere.
Use a spreader to distribute the seed at a rate of 2 to 3 pounds of seed per 1,000 square feet. You can use my free grass seed calculator and lawn size measuring tool to help you buy the right amount of seed for your property.
Add a thin layer (1/4″) of screened compost to top-dress at this time and use the flat/back side of your leaf rake to gently spread the compost/seed to ensure good contact across the lawn without burying your seed too deeply.
Water your lawn adequately to keep the soil moist for the first week, then steadily decrease the amount of water as the grass germinates and begins to grow. This will encourage your new seedlings to grow healthy roots that try to seek out water and make your lawn more resilient (but as discussed, don’t under-water your bluegrass).
Wait until your grass has grown to about 4 inches before mowing and make sure to mow no more than a third of the height at any given time.
I recommend bagging your clippings the first few times you mow your new bluegrass lawn, then mulching them back onto the lawn after that.
Overseeding Your Lawn with Kentucky Blue
If instead of starting a brand new lawn from seed you’re overseeding your lawn to help fill in bare spots, you want to make sure you use a high-quality grass seed and an aggressive cultivar of Kentucky bluegrass.
This way, your new grass will be able to fill in any spots more quickly while also crowding out weaker grass and weeds.
To overseed, mow your existing lawn very low and spread the grass seed and starter fertilizer.
I recommend dethatching your lawn and using a core aerator as well to make sure your new seed has plenty of room to take root, and good soil contact when you spread it.
Add fertilizer and compost, then use the back of a leaf rake to gently spread the compost and seed and ensure even coverage and optimal contact between soil and seed.
Of course you’ll want to water your seedlings appropriately to ensure good germination and growth. Let your grass grow to 4 inches before mowing, and bag your clippings the first few times you mow.
Kentucky Bluegrass Maintenance
Kentucky bluegrass will make your lawn look gorgeous, but it does require comparatively high maintenance.
To make it reach its full potential, you’ll need to put in a certain amount of work.
Watering Your Kentucky Blue Lawn
During optimal conditions in the spring or fall, Kentucky bluegrass requires 1 inch of water weekly.
During the hotter summer months, it requires 2 inches of water weekly, though at peak season more water will likely be necessary.
You can use sprinklers on a small lawn, but if you’re planning to grow a Kentucky Bluegrass lawn, consider an irrigation system. You’ll be glad you did.
What Height Should I Mow Kentucky Bluegrass?
As a cool season grass, Kentucky bluegrass performs best when mowed at a higher length, typically around 3 to 4 inches.
For comparison, warm season grasses, like Bermudagrass, can be mowed as low as 1 inch.
I find that growing your grass out longer helps reduce susceptibility to drought.
Potential Issues (and how to avoid them)
Kentucky bluegrass is more vulnerable to adverse lawn conditions.
Having your soil tested regularly is your best option to ensure your grass maintains optimal health. I do this at least once a year, in the spring, and use this kit from Amazon which you can send away for a lab analysis.
Kentucky Blue grows best in soil that has a pH level between 6.0 and 7.0. You can use lime to adjust your lawn’s pH if needed.
It can quickly lose its green color in soils with high alkaline content and may require more fertilizer than other grasses. However, be careful with the amount of fertilizer you use on it, as that may weaken the grass and open it up to diseases.
I use and recommend slow-release organic fertilizers which feed the soil rather than feeding the grass the way some synthetic fertilizers do.
This may seem like a lot of effort, but it can be easily accounted for with a lawncare routine and proper planning.
Most homeowners find that Kentucky bluegrass’s durability to high traffic and ability to self-repair more than make up for the amount of effort that goes into keeping it healthy.
Its high tolerance to the cold will also allow it to stay green and healthy looking for longer periods of the year than many other grass types.
Regions to Grow Kentucky Bluegrass
Kentucky bluegrass prefers cooler areas with shorter, mild summers. It grows best between 50 degrees and 60 degrees, so areas with clearly defined seasons are best.
Areas in the Midwest, like Kentucky, Ohio, and Tennessee are optimal zones. It is also found regularly in the northeast, like the New England states, as well as New York and Pennsylvania.
This type of grass also grows very well in the northwest United States in Washington, Oregon, and Idaho. It is grown mostly for commercial seed production there. There are farms in the Pacific Northwest that have Kentucky bluegrass grown to its full, unimpeded height of 18 to 24 inches where it can sway at its full color.
The further south you go in the country, the more difficult it will be to grow Kentucky bluegrass. It does not grow well in the hot areas around the Gulf of Mexico, or the southern Atlantic coast, like the Carolinas or Georgia.
Does a Kentucky Bluegrass Lawn Need Irrigation?
Due to the necessity of high water levels, it may be beneficial to you to install an irrigation system in your yard.
Doing so ensures your lawn will always have the proper amounts of water.
Newer irrigation systems can come equipped with moisture trackers, so they will adjust water levels throughout the season to keep your grass healthy.
An irrigation system will be most helpful during the peak summer months, but it can also help regulate Kentucky bluegrass through non-optimal growing conditions. While sprinklers likely won’t make it worthwhile to grow Kentucky bluegrass in Texas, it can help you maintain this beautiful grass type in a slightly warmer than optimal climate.
For completely optimal conditions, like those in the northeast or northwest regions of the United States, you will likely be able to get by without investing in an irrigation system, though having one will make maintenance more convenient.
Because Kentucky bluegrass is somewhat finicky, it is important to manage your water wisely. An irrigation system may improve your water efficiency.
Common Issues with Kentucky Bluegrass
Kentucky bluegrass has high susceptibility to certain diseases and lawn pests.
Overfertilizing Can Be a Problem
Using too much fertilizer increases risks of diseases such as leaf spot. This can be prevented by properly watering your lawn and not using excessive amounts of fertilizer.
High nitrogen levels are the true culprit, and there is a sweet spot to hit in terms of nitrogen amounts. Too much nitrogen will cause grass burnout, while too little will cause rust. If left unchecked, fungicide treatments may become necessary.
The amount of nitrogen necessary to keep your lawn looking healthy will vary depending on the size of your lawn. Typically, Kentucky bluegrass requires an annual amount of 4 to 5 pounds of nitrogen per 1,000 square feet.
Take Care of Thatch Buildup Regularly
Other preventative measures involve remediating thatch development and regularly aerating your lawn.
Kentucky bluegrass is a true sod-forming grass, and without extensive maintenance will develop thatch over time. Thatch will deprive your lawn of key nutrients and leave it increasingly vulnerable to diseases.
Dethatching your lawn every 3 to 4 years is a good measure to prevent ongoing issues. For especially well-established and dense lawns you may decide to aerate, detach, and overseed your lawn every other year in the early fall for best results.
While you can rent a reliable power rake for the job, with Kentucky Bluegrass lawns I recommend investing in your own tool for the job. It ends up being more cost effective in the long run since KBG requires regular dethatching.
The Dethatcher I Use & Recommend
For lawns up to a half acre there’s one clear choice when it comes to dethatching tools. I recommend The Greenworks 27022 10AMP Electric Dethatcher.
It works really well and will pay for itself after a few uses when compared to renting a power rake.
Proactively Treat for Grubs
Kentucky bluegrass is also particularly vulnerable to insect damage, like lawn grubs. Using preventative treatments for grubs is your safest option. It’s easier than getting rid of grubs once they’re damaging your lawn.
Adding beneficial nematodes to your yard in early spring, when grubs are nesting and have not hatched, is a good preventative method, and something I do each year in my lawn and garden. It’s a completely natural approach (you’re adding tiny, beneficial worms that seek out and eat the grub larva before they can do damage to your lawn).
Alternatively, if you notice damage to your yard, you can apply pesticides like this Scott’s product.
Insect damage occurs quickly and can be devastating to your yard. It’s best to monitor it and be proactive – I find prevention is easier and less expensive than treatment.
Kentucky Bluegrass: One of the Best Grasses for Lawns
Kentucky bluegrass is one of the most popular grass types in the United States.
Its deep, rich shade of blue-green is absolutely stunning when growing at its full potential. Its natural tendencies as a true sod-forming grass variety make it resilient for lawns with heavy foot traffic. Homeowners who choose it for their yard will love it for its growth habit and how it provides a uniform length and color.
For all these benefits, Kentucky bluegrass is somewhat higher maintenance than other grasses, like Fescues or Zoysia grass. However, it more than makes up for it with its positive qualities. Many people consider it the purist’s choice for lawns.
If you’re planning to grow Kentucky bluegrass in your yard, make sure your yard is well-suited for it.
It is vulnerable to heat and will require extra water under those conditions.
Even in the best of conditions, Kentucky bluegrass may require additional maintenance for it to reach its peak appearance. This may prove too costly for you. If you’re not a lawn geek, Fescue, or another turf type grass may be a better choice.
Regardless, if you do decide to take the leap, Kentucky Bluegrass can make your yard into an absolutely wonderful sight. It’s a lawn grass I can enthusiastically recommend to discerning homeowners with time, money, and a passion for lawn care.