One of the great things about Oklahoma is that we live in the transition zone.
What is the transition zone?
The transition zone is an area from northern Kansas to the Oklahoma-Texas border where you can grow both cool-season and warm-season turfgrasses. The transition zone can experience both hot summers and cold winters, often making it hard to decide between a warm-season lawn (Bermuda or Zoysia) or a cool-season lawn (fescue).
Why is that a good thing? Because we can successfully grow both warm season and cool season turfgrasses.
The most common turf in Oklahoma is Bermuda.
But, fescue, commonly thought of as only a shade grass, continues to increase in popularity as both a turfgrass suitable for shade and for full sun areas as well. It is now very common to find Bermuda lawns with at least some fescue.
Also, more and more lawn owners are realizing that fescue is more than a shade grass, it is a cool-season grass that can grow in full sun.
But, that can be a problem. You have to think very differently about how you care for a fescue lawn versus a Bermuda lawn.
Problem - Fescue won’t thrive, it will actually struggle to survive if it is fertilized like Bermuda. And, the same is true for Bermuda. Fertilize Bermuda like fescue and the result will be a thin, weak lawn.
Fertilizing cool-season lawns versus warm-season lawns requires a paradigm shift.
While Bermuda is approaching the end of its season, fescue is starting its season.
Let’s look at the differences.
Bermuda lawns are ending a season and need a low nitrogen, high potassium fertilizer to strengthen roots for the winter.
Spring Dead Spot is a disease that impacts bermuda lawns in the spring as the lawn is coming out of dormancy. One of the catalyst is heavy nitrogen applications in October applied in an effort to keep a warm season lawn green and active late into the fall.
Fall Fertilizer Applications:
Bermuda and Zoysia (Warm Season) –
Warm-season grasses are at the end of their growing season. In October and November, warm-season lawns don’t require nitrogen. With shorter days, cooler days, and nights, and the decrease in soil temperature, growth slows, and turf color fades.
Heavy nitrogen fertilizer during October in an effort to maintain color longer into the fall is harmful for Bermuda and a catalyst for Spring Dead Spot Disease.
The chances of having Spring Dead Spot Disease next year increases when nitrogen fertilizer is applied to a Bermuda lawn in the last 4-5 weeks before the first freeze, which in central Oklahoma is typically the first week of November.
So, if you are thinking your Bermuda lawn needs one more shot of nitrogen before the end of the season, don’t do it. There is a good chance you are doing more harm than good.
Bermuda, a warm season turfgrass,, performs best when fertilized with higher nitrogen during the summer month and low nitrogen fertilizer in the fall.
With cooler night time temperatures and shorter days, Bermuda lawns are slowing down. Resist the urgent to try keep them green and growing with high nitrogen fertilizer this month.
Because bermuda starts to thin out when it receives less than 6 hours of direct sunlight it is common to see lawns with both bermuda and fescue. The problem is you try to fertilize them the same, one will flourish and the other will struggle.
Fescue –
Fall is the beginning of a new season for fescue.
As temperatures begin to cool in September, fescue lawns start regaining color, thicken, and actively growing.
For fescue, fall is the same as spring is for Bermuda.
In April and May, as soil temperatures warm and Bermuda starts to grow, a higher nitrogen fertilizer is important. Again, fall for fescue is just like spring for Bermuda. Nitrogen, the first number on the fertilizer bag, helps thicken fescue, encourages new growth, and adds a deep rich color to the lawn.
Fall fertilizer applications on fescue will result in a healthier, thicker lawn. And don’t forget, a dense healthy lawn is the best defense against weeds.
A fertilizer application with at least 25% nitrogen to start the fescue growing season is important.
Newly seeded fescue lawns benefit from a fertilizer application anytime within the first 4 weeks after seeding.
The fertilizer differences continue throughout the year. Between now and next May, fescue performs best if it receives 4 pounds of nitrogen per 1,000 square feet.
Bermuda lawns are at their best when they receive their nitrogen between spring green-up in April and the end of September.
In early summer, while Bermuda needs high nitrogen fertilizer the only fertilizer needed for fescue is a low nitrogen, high potassium fertilizer to strengthen roots headed into the summer heat, similar to only fertilizer needs of Bermuda heading into the winter cold.
Fescue lawns are start a new season every fall. A high nitrogen fertilizer application now will increase color and turf density.
Fescue can be grown in full sun but it requires a very different fertilizer schedule compared to bermuda.
For a successful, fescue lawn, you have to think backward from a Bermuda lawn.
For a successful Bermuda lawn, you must think backward from a fescue lawn.
You can’t fertilize them both the same way and expect them both to respond the same way.
The Good News –
If you subscribe to Hall | Stewart’s 7-Step Lawn Care Program, whether you have Bermuda, Zoysia, fescue, or a combination of turfgrasses, we will make sure each type is receiving the correct fertilizer based on the current season and growing conditions. Our program recognizes that warm-season grasses and cool-season grasses have very different fertilization timing and needs.
If you have a overseeded fescue or are planning to this fall, don’t skip a fertilizer application. New seed grows rapidly and needs plenty of nutrition.
A healthy, thick and deep green fescue lawn next spring is easier to achieve with when a lawn receives the correct fall fertilizer applications.
Let’s cover one more misconception about fescue in the fall:
Myth - If you are seeding fescue in the fall, it should not receive any lawn care applications.
Not true…
Fact - Fertilizer applications are not only very important for the existing fescue, but it also plays a critical role in the establishment of new seed.
Yes, if you are seeding you should not apply a pre-emergent herbicide until the seed has come up and the lawn has been mowed 2 or 3 times.
But, fertilizer anytime within the first 4 weeks of seeding will provide the seed the nourishment it needs as the new seedlings germinate and begin to grow rapidly.
The challenge for lawns with both warm season and cool season turf is they require the exact opposite timing of fertilizer applications for them both to thrive.
Summary:
Bermuda lawns benefit from receiving their last high-nitrogen fertilizer application before the end of September.
Fescue lawns are starting a new season and require a high-nitrogen fertilizer as they regain color, thicken, and grow.
Both are important.
For the best lawn, it is important to know your turf type and fertilize at the correct time of the year.
If you need have questions or need help understanding the fertilizer needs of your lawn, we would love to help.
Lorne Hall
Hall | Stewart Lawn + Landscape
(405)367-3873