Fertilize cool-season grasses in Oklahoma between March and May and again between September and October. For warm-season grasses, the best times to fertilize in Oklahoma is from May to June and September to October.
Fertilizing at these times ensures your lawn stays green and healthy year-round.
When to fertilize cool-season grass
Oklahoma gets warm summers and cold winters. Kentucky bluegrass and perennial ryegrass perform exceptionally well in northern Oklahoma, while tall fescue thrives throughout the state. Check out our guide on the best grasses for Oklahoma lawns.
Cool-season grasses grow vigorously in early spring and fall when temperatures range between 55 and 75 degrees Fahrenheit.
The best time to fertilize cool-season grasses is between September and October, when temperatures range from 60 to 70 degrees Fahrenheit. This promotes strong root growth in the spring when the grass emerges from its winter slumber, as the illustration above shows.
Apply the second round of fertilizer in early- to mid-spring, between March and April, when temperatures range from 55 to 65 degrees Fahrenheit. However, avoid fertilizing later in the spring so you don’t force your grass to grow past its natural growth season.
When to fertilize warm-season grass
Buffalograss, Bermudagrass, St. Augustinegrass, and Zoysiagrass perform relatively well throughout Oklahoma, but we recommend overseeding them with annual ryegrass to help retain their color.
Warm-season grasses grow actively in late spring and summer when temperatures range between 75 and 90 degrees Fahrenheit.
The best time to fertilize warm-season grasses in Oklahoma is from mid-spring to early summer (April to June) when temperatures range from 75 to 85 degrees Fahrenheit.
Apply the second round of fertilizer in August, when temperatures hover around 90 degrees Fahrenheit. Avoid fertilizing in the fall so you don’t force your grass to grow beyond its active growth season.
Fertilizer calendar for Oklahoma
Here’s a handy calendar to help you know when to fertilize your Oklahoma lawn.
| Month | Kentucky Bluegrass | Perennial Ryegrass | Tall Fescue | Bermudagrass | Buffalograss | St. Augustinegrass | Zoysiagrass |
| January | |||||||
| February | |||||||
| March | ✔ | ✔ | ✔ | ||||
| April | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ |
| May | Possible | Possible | Possible | ✔ | ✔ | ✔ | ✔ |
| June | ✔ | ✔ | ✔ | ✔ | |||
| July | Possible | Possible | Possible | Possible | |||
| August | ✔ | ✔ | ✔ | ✔ | |||
| September | ✔ | ✔ | ✔ | Possible | Possible | Possible | Possible |
| October | ✔ | ✔ | ✔ | ||||
| November | Possible | Possible | Possible | ||||
| December |
More Lawn Care and Landscaping Resources for Oklahoma:
- When to Plant Grass Seed in Oklahoma
- Month-to-Month Oklahoma Lawn Care Schedule
- When to Aerate Your Lawn in Oklahoma
FAQs
Should I fertilize my lawn before or after aerating?
Aerate your lawn before fertilizing to help the soil absorb nutrients more effectively. We recommend fertilizing your grass within 48 hours after aerating for the best results.
How can I tell if my lawn needs fertilizing?
If your grass turns yellow or develops thinning patches, you should fertilize your lawn.
Can I fertilize my Oklahoma lawn when it’s raining?
It’s a good idea to fertilize before a light rain because the water helps your grass absorb the nutrients. However, avoid fertilizing during heavy downpours, as the rain will wash away nutrients into storm drains and impact aquatic life.
When to hire a professional
Lawn maintenance can be tiring and time-consuming, but it’s crucial to keep your yard looking good. If you need help fertilizing your grass or with anything related to lawn maintenance, get in touch with Lawn Love. Our seasoned pros can transform your garden from boring to beautiful.
Main Image Credit: ronstik | Adobe Stock Free | License
