How Fast Does Kentucky Bluegrass Spread?

Under ideal conditions, 1 Kentucky Bluegrass seed can grow to cover one square foot of lawn in a single growing season (spring through fall). Established Bluegrass lawns can fill damaged areas up to 24 inches (60 cm) in diameter in a growing season. This growth rate is excellent among turf grasses. Kentucky Bluegrass has the fastest ability to spread and fill damaged areas of any cool-season turf grass.

If you are looking to seed a new yard and have it fill in quickly, or are thinking of overseeding your lawn, Kentucky Bluegrass is the best choice for cool-season lawns in the United States and Canada.

How fast does Kentucky Bluegrass spread?

Does Kentucky Bluegrass Spread Faster than Other Grasses?

New Kentucky Bluegrass blades growing and filling in a Kentucky Bluegrass lawn.
New Kentucky Bluegrass coming up in my lawn during the growing season.

Kentucky Bluegrass spreads faster than its competitor grasses. This is because Kentucky Bluegrass (or KBG) sends out rhizomes (long roots) in both spring and late summer. Each rhizome has a node every few inches, which will form a new grass plant and send out its own roots and blades. In comparison, other cool-season grasses grow in bunches and don’t produce many rhizomes.

  • Kentucky Bluegrass spreads faster than other cool-season grasses, such as Rye and Fescue.
  • Bluegrass rhizomes spread in a network, turning Kentucky Bluegrass lawns into a thick sod lawn.
  • Rye and Fescue tend to grow in bunches and don’t form root networks.

Kentucky Bluegrass is a common choice for high-traffic lawns, sports fields, and golf courses because it spreads so quickly. It repairs damage from foot and vehicle traffic at a quick rate.

Up close shot of new Kentucky Bluegrass growing into an established lawn
This is what new Kentucky Bluegrass looks like. Don’t mistake it for weeds growing in your lawn.

Kentucky Bluegrass: Slow to Seed, Quick to Spread

Kentucky Bluegrass takes longer to sprout from seed than other cool-season grasses. It may be as long as 2 weeks after you spread your Bluegrass seed before you begin to see seedlings emerge. In comparison, many varieties of Fescue and Ryegrass begin to sprout within a week.

  • Kentucky Bluegrass seed sprouts in 14 days.
  • Fescue and Ryegrass typically sprout in 5–10 days.
  • Once sprouted, Kentucky Bluegrass spreads to fill a lawn much faster than other grasses.

Remain patient and follow Kentucky Bluegrass water requirements until it begins to take root. A Kentucky Bluegrass lawn seeded in spring will spread through the soil and fill out by fall. If you seed in the fall, your lawn will be fully established by the middle of the following summer.

If the Kentucky Bluegrass seed you’re using isn’t working, I have found a lot of success with Smart Seed grass seed plus fertilizer by Pennington. The added fertilizer in the seed helps take a step out later in the process.

A 6,600 sq ft coverage bag of Pennington Smart Seed Grass Seed plus Fertilizer laying on a Kentucky Bluegrass lawn.
Pennington Smart Seed grass seed and fertilizer works great on my Kentucky Bluegrass lawn.
Grass Seed and Fertilizer Mix for Your Kentucky Bluegrass Lawn
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How To Encourage Kentucky Bluegrass to Spread Faster

In order to get the most out of your Bluegrass, give it the essentials: water and nutrients. If you are seeding a bare lawn or bare patch, make sure to prepare the ground, lightly cover the seed, and keep the soil moist to increase the germination rate and drive faster grass spread.

Watering new Kentucky Bluegrass seed is one of the most crucial steps for successful growth. I know I’ve struggled with providing enough water in the past, especially when I’m out for a weekend and can’t turn my sprinklers on. I eventually started using this scheduled watering timer by Rain Bird and now all the new seed I lay down gets water on a scheduled timer, whether I’m home or not.

A close up shot of a Rain Bird scheduled watering timer attached to the water spigot of a single family home.
I can set the specific days, times, and duration for my Kentucky Bluegrass to get watered.
Automate Your Lawn and Garden Watering
Lawn and Garden Watering Timer | Rain Bird
  • Advanced Scheduling: This easy-to-use 7-day digital timer is ideal for use with hose-end sprinklers, drip irrigation, and soaker hose, allowing you to program up to two watering times per day, any day(s) of the week.
  • Flexible Watering: It's perfect for watering all areas of your yard, including gardens, landscaping beds, and both newly seeded and established lawns, with a working water pressure of 15 psi (minimum) – 90 psi (maximum).
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  • When seeding new Bluegrass, keep the soil moist until the seeds begin to sprout. This will ensure higher germination rates. The more seedlings you get, the faster the grass will spread.
  • Provide 1 inch of water per week to established Kentucky Bluegrass in cool weather. Increase to 2 inches per week in temperatures above 75℉ (24℃).
  • Make sure to water during drought periods. Kentucky Bluegrass has shallow roots easily stricken by drought and heat. Growth may slow in peak summer temperatures.
  • Follow a Kentucky Bluegrass fertilizer schedule where you apply fertilizer 2–4 times throughout the growing season to maximize spread. A Kentucky Bluegrass lawn requires 3–6 pounds of nitrogen per 1,000 square feet annually.
  • Proper mowing height for Kentucky Bluegrass is 2.5–3 inches. This height maximizes leaf blade growth and grass spread.

By following a watering and fertilizer schedule for Kentucky Bluegrass, you will maximize grass growth and spread. Poorly maintained Bluegrass lawns may struggle and spread more slowly. Provide your Bluegrass lawn with the essentials and you will be rewarded with impressive growth through spring, summer, and fall.

Does Kentucky Bluegrass Spread on its Own?

Kentucky Bluegrass will send out rhizomes and spread on its own as long as it is fertilized, kept from suffering drought, and is maintained with regular mowing. This is in direct contrast to Rye and Tall Fescue, which are the other common turf grass varieties in regions where KBG grows. These grasses grow in bunches and new seed must be cast to encourage spread.

  • Kentucky Bluegrass spreads on its own as long as it is properly maintained.
  • Other cool-season grasses must be spread to new areas via seeding.

Although the Kentucky Bluegrass rhizomes aren’t visible, they are spreading beneath the soil. Look for new sprouts filling in your lawn in spring and late summer.

Will Kentucky Bluegrass Fill in Bare Spots?

Kentucky Bluegrass will fill bare spots in your lawn naturally. Damage caused by traffic, pet use, or excavation will be reclaimed as Kentucky Bluegrass sends rhizomes into the soil.

A circle and arrow pointing out a bare spot in a Kentucky Bluegrass lawn that will fill in over time with proper watering and fertilization to the entire lawn and yard.
This bare spot in my Kentucky Bluegrass lawn will fill in over time with proper watering and fertilization to my entire yard.
  • Established Kentucky Bluegrass will fill in bare spots up to 24 inches (60 cm) in diameter over the course of a single growing season.
  • Reclaim large bare spots and prevent weeds from taking hold. You can do this by reseeding bare soil with Kentucky Bluegrass in spring or fall.

If your lawn has small bare spots where grass has been damaged, you can encourage Kentucky Bluegrass to fill the area quickly through cultivation, watering, and mowing. Reseeding is only necessary for bare spots larger than 24 inches (60 cm) in diameter.

Does Kentucky Bluegrass Spread Quickly?

Kentucky Bluegrass spreads faster than other turf grass varieties grown in the same climate. A single Kentucky Bluegrass seed can grow to fill a square foot of lawn over the course of a single growing season. Because it spreads naturally, Kentucky Bluegrass resists weeds, repairs itself, and forms a lush lawn.

To encourage your Bluegrass lawn to spread quickly, apply nitrogen fertilizer regularly throughout the growing season, provide 1–2 inches of water per week, and practice proper mowing methods. This will cause your Bluegrass to leaf out much more quickly than Ryegrasses and Tall Fescues, resulting in the most beautiful lawn that can be grown in northern climates.

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