Tall fescue is a cool-season grass, and it is known for its ability to grow in a variety of soil and environmental conditions.
The deep root system of tall fescue provides superior heat and drought tolerance.
This makes it a popular choice for cool-season lawns in transitional growing zones.
Since tall fescue has a bunch-type growth habit, it does not spread, which could lead to bare spots across your lawn.
Many homeowners mix tall fescue with other grass types to counteract bare spots.
But what is the best grass to mix with tall fescue?
Kentucky bluegrass is considered the best to mix with tall fescue because it is also a cool-season grass with similar growing conditions. Avoid mixing tall fescue with warm-season grasses like zoysia or Bermuda grass, as this will result in a patchy lawn in summer and winter.
Overseeding tall fescue with another grass type keeps your entire lawn healthy by increasing its pest and disease resistance.
Kentucky bluegrass will make your tall fescue lawn more uniform.
It does this by filling in bare spots and choking out annual grass and broadleaf weeds.
Read on to learn more about mixing Kentucky bluegrass with tall fescue and what to know before getting started.
Table of Contents
The Best Grass to Mix with Tall Fescue
Since tall fescue is a cool-season grass, it thrives in zones 3-7, which includes the transitional zone.
Tall fescue has excellent heat and drought resistance, making it less likely to go completely dormant during a hot summer.
If you live above the transitional zone, Kentucky bluegrass will be the best type of grass to add to a tall fescue lawn.
Kentucky bluegrass will grow in the transitional zone if the summers are not too hot.
While perennial ryegrass grows in the same hardiness zones as tall fescue, mixing them in the same lawn is not a good plan.
Perennial ryegrass has different care requirements compared to tall fescue.
Planting them together will result in much extra lawn maintenance with less than ideal results.
For regions with very high summer temperatures, you may be tempted to mix your tall fescue with warm-season grasses like zoysia or Bermuda grass.
However, mixing cool-season and warm-season types of grass is a bad idea.
Mixing these two very different grass species will result in a patchy lawn in summer and dead grass in winter.
Zoysia and Bermuda grass are also very likely to overtake tall fescue because they spread quickly.
Further Reading: Why Fescue grass doesn’t spread well
In some regions, Bermuda grass is considered an invasive weed.
Mixing Kentucky Bluegrass with Tall Fescue
Kentucky bluegrass blends well with tall fescue.
It will fill in areas of damaged grass in your existing lawn or bare spots caused by the bunch-type growth habit of fescue.
Choose a seed mix with 10% Kentucky bluegrass blend and 90% tall fescue for the best results.
This seed ratio prevents the Kentucky bluegrass from overcrowding the tall fescue.
A seed mix like this one is already blended to the ideal ratio of tall fescue and Kentucky bluegrass, so you must determine how much you need.
Most seed mixes include the mix ratio on the product label.
How much seed you purchase will depend on the condition of your existing lawn.
If your lawn is already well-established, you will spread 2-4 pounds of seed per 1,000′ square feet.
For lawns with bare spots, increase the amount to 4-8 pounds of seed per 1,000′ square feet.
When seeding a deteriorated lawn or bare ground, 8-12 pounds of seed per 1,000′ square feet is required for full coverage.
Grass Seed Application Tips
To increase the germination rate of your entire lawn, spread the Kentucky bluegrass and tall fescue mix from late August to early September.
Use a rotary or drop-type spreader to ensure uniform application over your entire lawn.
It is also recommended to plant grass seeds when soil temperatures are between 50-65° degrees Fahrenheit (18° C).
Use a lawn roller to ensure they make good soil contact after spreading the seeds.
Keep the soil surface moist by watering every day for the first 14 days after application.
Once the seedlings are around 2″ inches in height, you may switch to a weekly watering schedule.
Around 1″ inch of water per week is recommended to maintain a healthy lawn.
Applying a ½” inch of water every third day is better to keep your yard from becoming soggy.
The early morning hours are the best time to water your grass because it reduces the amount of evaporation and the risk of disease.
Plant cool-season grasses in the fall to establish a healthy root system.
Winter or late spring planting of tall fescue and Kentucky Bluegrass is not recommended.
It will be more difficult for them to survive the hot summer months in a transitional zone.
What To Know Before Mixing Tall Fescue with Other Grasses
Before mixing tall fescue with another type of grass on your cool-season lawn, there are a few important steps.
You will need to consider the following parts of your lawn environment for the best results:
- Your growing zone
- The amount of sunlight on your lawn
- Seed mix ratios
- Soil type
Doing research ahead of time ensures a healthy lawn and helps maintain a lush appearance.
Consider Your Growing Zone
The United States Department of Agriculture has divided the country into 11 hardiness zones.
These zones are based on the average minimum temperature for each region.
Zone 1 is based on an average minimum temperature of -50° degrees Fahrenheit (-45° C).
Zone 11 has average minimum temperatures above 40° degrees Fahrenheit (4° C).
The continental United States contains hardiness zones 3 through 10.
Zones 1 and 2 are found in Alaska, and zone 11 includes the Hawaiian islands.
Attempting to grow grass or other plant life not intended for the hardiness zone in your region will not produce good results.
Homeowners in the transition zone face challenges in choosing which grass will do well in their area.
Zone 7 is a transitional zone because it experiences both cold winters and hot summers.
Cool-season grasses may die out in the summer heat, and the cold winter is usually too harsh for most warm-season grasses.
Tall fescue creates a cool-season lawn and will grow in and above the transitional zone.
The excellent drought tolerance of tall fescue means it will survive prolonged periods without rain as long as temperatures are not too hot.
The table below shows common grass types and their preferred growing zones.
|Grass Type||Preferred USDA Hardiness Zone|
|Tall fescue||Zones 3-7|
|Kentucky bluegrass||Zones 3-7|
|Bermuda grass||Zones 7-10|
|St. Augustine||Zones 8-10|
|Perennial ryegrass||Zones 3-6|
Always review the USDA’s Hardiness Zone map each year, as the zones may change due to climate shifts.
How Much Sun Does Your Lawn Receive?
Evaluating how much sunlight and shade your entire lawn receives throughout the day is essential.
Tall fescue grows well in either full sun or shade, but other grass types may have different needs.
Kentucky bluegrass prefers full sunlight but will also tolerate light shade.
St. Augustine grass will tolerate partial shade, but it is not as cold-hardy as tall fescue and will die out quickly if temperatures are too low.
Understand Seed Mix Ratios
The ratio of the types of seeds in a mix is important.
Kentucky bluegrass and zoysia grass spread more quickly than tall fescue.
A high ratio of these grass types in a tall fescue mix will result in the fescue being overwhelmed and possibly choked out by the more aggressive grasses.
Soil Type and Fertilization
Tall fescue is suitable for well-draining soils with a pH between 5.5 to 6.5.
Testing your soil is crucial for knowing what soil amendments to add for a healthy lawn.
Be sure to take plugs of soil from different areas of your lawn for more accurate results.
Soil samples from one area of your yard may require different nutrients than soil samples from another.
Soil pH determines which nutrients are available to plants.
For example, soil with a pH of 6 allows more nitrogen to reach grass than soil with a pH of 5.
Kentucky bluegrass does well in acidic soils with a pH close to 6, making it compatible with tall fescue.
Knowing your soil makeup will also help you choose the proper fertilizer.
Tall fescue and Kentucky bluegrass have very similar fertilization needs.
If you do not want to use a commercial fertilizer, several companies offer products for organic lawn care.
These organic fertilizers are typically plant-based, although some contain animal manure.
Always read the product labels on any fertilizer you choose to avoid applying too much and ending up with burnt or dead grass.
Your soil sample test results will tell you which nutrients your lawn is lacking, so you will be able to tailor the fertilizer to your specific needs to keep your lawn healthy.
Establishing a routine maintenance schedule will ensure a lush, healthy lawn.