While it is the de facto king of lawn grasses, Kentucky Bluegrass is relatively high maintenance and needs a lot of work to look as good as it can be. It is a cool-season grass though it also has relatively good heat-resistance. If you live in a mild and temperate area of the country, Kentucky bluegrass can populate your yard year-round.
Despite the name, Kentucky Bluegrass is not native to the state of Kentucky. It actually originates from Europe and Asia, although it is very common in pasture states of the US like Kentucky, thus explaining its name.
Kentucky bluegrass is a perennial grass, meaning that it will come back year after year, provided it is adequately maintained. It grows the best in the cold season between October-May. It has very high cold-resistance and is used extensively in the northern parts of the US.
Given that it is a cold season grass, Kentucky bluegrass has relatively short roots and does not anchor into the ground very far. As such, it can be in danger in hot, arid climates, which is why it is not as popular in the south and southwestern United States. That being said, if it is heavily watered and irrigated, Kentucky bluegrass can survive and flourish in the arid states of the south.
Kentucky bluegrass is kind of a funny name. After all, what kind of grass is blue? And you are right; Kentucky bluegrass is not named for its blades because they are always green. Rather, if you let Kentucky bluegrass grow to its natural height, it will produce small blue flowers that grow from the top of its stems. Granted, most people cut the grass before it gets this tall, leaving many perplexed why it has this name.
Kentucky bluegrass is a cold-season grass, and it is the most hearty cold-season type out of common grasses used in the US. It usually grows best in temperate climates that are not too cold and not too hot. Like most other types of grass, it sprouts rhizomes that form a dense thatch and grows exceptionally well on moist, well-drained yards. The optimal temperature ranges for Kentucky Bluegrass are between 60-90 degrees-F.
Since Kentucky Bluegrass relies on its dense rhizome structure, it grows less quickly than some other grass varieties. It takes a fair amount of time to germinate, but once it does, it forms a dense layer of sod and develops into a thick, lush turf that is soft to the touch and is very resistant to foot traffic and the elements. As such, it can recover from damage relatively easily.
Kentucky bluegrass will lose moisture and dry out in the sun, but it is resistant and usually springs back once the colder months hit. Extreme heat and drought can kill it, but as long as you keep it properly watered, it will stay dormant during the summer and come back to life in the early fall. Kentucky bluegrass normally grows best in yards that get a lot of sunlight, though there are variants that can grow well in the shade.
The best time to plant Kentucky Bluegrass is right after the hottest months of the year, so around mid-September. Growth will peak in the following months and through the winter. Kentucky bluegrass grows quickly once it establishes, so it develops thick layers of thatch. This thatch can be a detriment to moisture absorption if you plant it during the hotter months.
Before planting Kentucky bluegrass seed, you must prepare your yard. The top 1-2 inches of soil needs to be tilled, and the yard needs to be thoroughly watered first. Kentucky bluegrass also grows best with a consistent fertilizer schedule.
Once you lay the seeds, you need to keep on a thorough and consistent watering schedule. The grass will not establish roots and grow well if it doesn’t get water during the first few critical weeks after planting. Right after laying the seed, you need to stay on a consistent schedule of watering it multiple times a day before it starts to sprout. After about 2-3 weeks, the grass should have taken root and started to grow. It takes a while for Kentucky bluegrass to germinate, but once it does it spreads rapidly due to its dense and extensive rhizome structure.
Once the grass has reached about 3 inches high, you can mow it for the first time. Like most other types of cool-season grasses, it is cut longer than warm-season grasses. Be sure that you do not cut more than 1 inch off the grass; any lower and you run the risk of pulling the roots out of the ground. During the hot months, you should keep the grass longer at around 3-3 ½ inches.
Also, Kentucky bluegrass requires a specific soil pH to grow. The optimal soil pH for growth is between 5.8-7.0, so slightly on the acidic side. If the pH is off, the grass can lose its vibrant emerald color. We recommend testing your soil pH every 2-3 years to make sure it’s in the right range. Fertilizers and mineral supplements can keep your soil in good growing condition.
In addition to the traditional variety, there are several special varieties of Kentucky bluegrass that might tolerate heat-stress better or have less watering requirements. Bluegrass seed will often be sold with multiple variants in one package so that each type can reinforce one another.