The best time to fertilize your lawn in Tennessee is between March and November, but the timing will vary depending on where you live in the state and your grass type.
Tennessee supports both cool- and warm-season grasses. Fertilize your cool-season grasses in the fall (September to November) and your warm-season varieties from spring to late summer (mid-March to early September). However, your locality and weather patterns greatly impact the ideal fertilization time for you, as we will explain further.
Best time to fertilize your Tennessee lawn by grass type
Tennessee is in the transition zone, so both cool- and warm-season grasses thrive here. However, these grass types are quite different in terms of lawn care.
As for fertilization, you’ll have different timelines for cool-season and warm-season grasses. Let’s take a look:
Fertilize cool-season grasses: September, October, and November
After the summer months end, your cool-season grasses, such as Kentucky bluegrass, perennial ryegrass, and fescues, will need a push for its upcoming growing season.
First dose
Apply a suitable fertilizer in September, preferably mid-September when the daytime temperatures get between 60 and 75 degrees Fahrenheit and soil temperatures start to cool down but still stay above 45 degrees Fahrenheit. Here’s a detailed guide that’ll help you decide what’s a suitable fertilizer for your lawn.
Second dose
Give a second dose in October when the soil temperatures are still consistently above 45 degrees Fahrenheit.
Third dose
Finally, before the winter sets in, give a last dose of a nitrogen-only fertilizer in November to ensure that your turfgrass stores energy for winter and retains much of its color.
Applying fertilizer in the spring might sound tempting – for all of us want our lawns to grow and fill up as soon as the air gets a bit warmer. But it isn’t healthy for cool-season grass that already has a flush of shoot growth.
The Kansas State Extension recommends that if you have to, you must wait until the flush is over to fertilize cool-season grasses. This typically happens late in the spring.
Tips from a pro: Never apply more than a pound of fertilizer per 1,000 square feet of land because the excess might leak into waterways and pollute the surroundings. For more, take a look at this guide.
Fertilize warm-season grasses: March to June and September
Warm-season grasses have their growth season from spring to summer and then they enter dormancy as the temperatures drop.
First dose
Apply a suitable fertilizer to your lawn between mid-March to early April when the soil temperatures start to consistently stay above 55 degrees Fahrenheit. You will notice the grass greening up after winter dormancy around this time. Early applications will help set the foundation for a healthy growing season.
Second dose
When the grass starts growing actively, i.e., when daytime temperatures stay consistently between the 80s and 90s, apply a second dose. This should be around late May to early June to support lush, green, and resilient turf growth.
Third dose
When the temperatures begin to cool down but the grass is still actively growing, around late August or early September, give your lawn a last fertilizer dose. This will help strengthen the root system and prepare your lawn to survive through winter dormancy.
Ideal time to fertilize by regions in Tennessee
Tennessee has a diverse geography, running from cool mountains in the east to flat, warmer areas in the west. So the change in climate zones requires a different approach to fertilizing.
Western Tennessee
West Tennessee is warmer and slightly more humid than the rest of the state. Higher temperatures here bring about an earlier growing season. So homeowners in western Tennessee should fertilize slightly earlier in the spring and late summer.
For warm-season grasses
Schedule the first dose of fertilizer in mid-March.
For cool-season grasses
These grasses might go through more stress due to prolonged heat in this region. Complete the fall fertilization early, in early September, to help grass recover from summer stress.
Middle Tennessee
The middle has a moderate climate, somewhere in between the temperatures of the west and east. Generally, middle Tennessee follows the standard fertilization schedule as discussed above.
Eastern Tennessee
The east is cooler, so the weather warms later and cools earlier.
For warm-season grasses
Fertilize a week or two later to ensure that the soil is warm enough and optimal for grass to absorb nutrients. This should be around mid-April, with second and third applications in early June and early September.
For cool-season grasses
Apply the first dose in late September, the second in mid-November, and the third in mid-March.
What makes a time “ideal” for fertilization?
The “ideal” time is essentially just a set of conditions that need to align for your grass to be able to absorb nutrients effectively. You must perfect the fertilization timing in your yearly lawn care schedule because each grass type needs certain environmental conditions for optimal growth and health. Let’s take a look:
Soil temperature
Warm-season grasses
These grasses begin to grow actively when soil temperatures rise and consistently stay above 55 degrees Fahrenheit. If you fertilize early, the grass won’t absorb the nutrients and if you get too late when the grass has cooled down, it will encourage late-season growth.
Late growth means the grass won’t have time to develop deep, strong roots before winter and will risk winter damage. Plus, it’ll be too near to the time grass stops growing and will simply lead to weak turf.
Cool-season grasses
Soil temperatures between 45 and 75 degrees support growth for these grasses. Fertilizing during these temperatures allows the grass to absorb nutrients more effectively and develop stronger roots in fall and early and strong in spring.
Fertilizing outside this temperature range will stress the grass and leave you with a weak lawn.
Rainfall and moisture levels
The soil in your Tennessee lawn must have adequate moisture so that the fertilizer absorbed by the soil is taken up by grass roots efficiently. Fertilizing when the soil is too moist already, or right before heavy rains are predicted may cause runoff.
Ideally, apply fertilizer before light rain and avoid feeding the grass during periods of drought as it will stress the grass and won’t allow nutrient absorption.
Peak growth periods
Cool- and warm-season grasses have different growth cycles. Each has a period or season of rapid growth and that’s when you need to provide the grass with essential nutrients to grow.
Fertilizing during peak growth periods (late spring and summer for warm-season grasses and fall and early spring for cool-season grasses) ensures that your grass receives all the good minerals to support healthy growth.
Not just that, it also helps the grass develop a strong root system, recover from winter or heat stress, and maintain thickness.
Other useful resources about lawn care in Tennessee you might want to check:
- When to Plant Grass in Tennessee
- When to Aerate Your Lawn in Tennessee
- When to Apply Pre-Emergent in Tennessee
- Common Weeds in Tennessee
- When to Plant Clover in Tennessee
Get help from a pro
Timing is crucial with lawn fertilization, but timing is also hard to keep up with. Especially in Tennessee where we get all four seasons. So skip the guesswork and let a local lawn pro near you help out. They know exactly what your grass needs and will help you master a suitable fertilization schedule.
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