Spring in Knoxville arrives in waves because of late-season cold snaps, and it brings with it a lot of yard work. Follow our spring lawn care checklist to get your lawn ready for the first mow of the season.
What makes spring lawn care in Knoxville challenging: Winters bring heavy rain and fluctuating temperatures that are tough on grass. Our heavy red clay soil adds another layer of difficulty because it stays wet longer and compacts easily.
1. Prepare your lawn mower
Spring arrives quickly in East Tennessee, so late February or early March is the best time to check your lawn mower and other equipment.
If you wait until the grass is already tall in March, you might find your mower won’t start, or worse, it could break down halfway through the job.
Here’s how to get your lawn mower ready for the first mow of spring:
- Sharpen lawn mower blades: Dull lawn mower blades tear the grass tips, which turns them brown and invites lawn diseases.
- Change the oil: Dirty oil hurts your lawn mower’s engine; fresh oil keeps it running cool and helps it last for years. Change the oil once a year at the start of the season (or every 50 hours of use).
- Replace spark plugs: A clean spark plug ensures reliable starting, saving you from frustration on the first warm day.
Read more: Best Lawn Mower Maintenance Practices
2. Rake up yard debris
Winter storms in Knoxville often knock down branches and twigs. You probably also have a collection of sweetgum balls on your lawn.
These spiky fruits from sweetgum trees do not decompose quickly. They can dull your mower blades or turn into dangerous projectiles if you run over them. Rake up sweetgum balls or use a rolling nut gatherer to clear them before your grass gets tall.
Warning: Be careful with our local red clay soil. Raking or walking heavily on soggy clay compacts it, suffocating grass roots and creating hardpan layers that resist water. Aim to clean up your yard in late February to early March, but only after a few dry days when the ground isn’t squishy.
Good to know: City of Knoxville Public Service crews collect brush every two weeks from March through October. Set your brush out by 7 a.m. on the Monday of your scheduled week. Keep your pile smaller than 6 feet by 6 feet by 6 feet.
3. Test your soil
East Tennessee’s native red clay is naturally acidic and often locks away nutrients your grass needs to survive the humid summer. A soil test reveals exactly what your lawn needs.
While late fall is the gold standard for soil testing because it allows lime several months to correct pH, early spring (late February to early March) is your next best option. If you missed the fall window, test now before spreading any chemicals.
Warning: Do not collect samples when the ground is soggy from spring rains. Wet clay clumps into bricks, making it impossible to mix a proper composite sample. Wait for the soil to dry enough to crumble easily.
Good to know: You can pick up soil test boxes at the Knox County UT Extension Office (Downtown West Boulevard) or at local partners like Mayo Garden Centers. Mail your soil samples to the UT Soil, Plant, and Pest Center in Nashville for a precise analysis.
Read more: How to Soil Test Your Lawn
4. Treat lawn diseases
Knoxville’s wet, cool springs create the perfect breeding ground for fungal lawn diseases. Inspect your lawn as it greens up. If you see issues, identify the specific fungus because treating the wrong one wastes money.
Most spring lawn diseases on cool-season grass like fescue are minor and may pass on their own, but warm-season grasses often struggle with damage left over from winter.
Here is what to look for and how to handle it:
- Snow mold (March): If you find matted, crusty gray or pink circles after winter snow melts, gently rake the area to break the crust and increase airflow to dry it out.
- Red thread (March to May): Pinkish-red threads on fescue tips indicate nitrogen deficiency during cool, moist weather. Apply nitrogen fertilizer to help the grass outgrow this mild infection without using fungicides.
- Large patch (April to May): Active on Zoysia and Bermudagrass, this fungus is most active in cool, moist conditions (50 to 70 degrees). Look for expanding orange circles. Stop nitrogen immediately to starve the fungus; apply fungicide if severe.
- Spring dead spot (April to May): Bleached, sunken patches on Bermudagrass appear at green-up, but infection happened last fall. Apply preventive fungicides in October; spring applications arrive too late. Fertilize only in summer to encourage root recovery.
Note: A healthy, well-maintained lawn is your best defense against lawn diseases. Proper mowing and aeration prevent most issues before they start.
Good to know: If you are unsure what lawn disease you are looking at, the University of Tennessee’s Soil, Plant and Pest Center accepts physical samples for accurate diagnosis. You also can submit digital photos through your local county extension agent.
Read More: How to Identify and Treat Grass Fungus
5. Control lawn pests
As soil temperatures rise in Knoxville (starting in March), overwintering insects become active. Most spring lawn pest activity is minor and often passes on its own.
However, you must distinguish between lawn pests that require immediate “rescue” treatments and those that can be better managed later. Inspect your lawn by tugging on brown patches; if the grass lifts like a loose carpet, you likely have a root-feeding infestation.
Warm-season grasses (Zoysia, bermuda) are particularly vulnerable to billbugs in spring, while cool-season fescue often reveals lingering grub damage from the previous fall.
Here is what to look for and how to handle it:
- White grubs (March to April): Look for loose turf or skunks digging up your yard. Since mature larvae are hard to kill in spring, wait to apply preventative treatments in June or July.
- Armyworms (April to May): These caterpillars chew cool-season fescue blades, stripping your lawn. If you spot heavy feeding damage, apply curative insecticides immediately, as the damage does not resolve on its own.
- Billbugs (April to May): Active on Zoysia and bermudagrass, weevils wander on pavement in spring. Apply preventative insecticides now to stop larvae from hollowing out stems later in the summer.
- Fire ants (late April to early May): Mounds appear as the soil warms up (soil temperatures reach 70 to 90 degrees). Broadcast fire ant bait over your entire lawn rather than just treating individual mounds for the most effective, long-term control.
Warning: Always identify the specific lawn pest before applying insecticides, as applying the wrong product wastes money and harms beneficial insects. If you suspect an infestation but can’t identify the lawn pest, contact the Knox County Extension office before spraying.
Read more: Guide to Using Pesticides on Your Lawn
6. Apply pre-emergent herbicide
Spring weed control in Knoxville requires precise timing and identification. For example, to prevent crabgrass germination, apply pre-emergent herbicides in late February to mid-March, specifically before dogwoods bloom (or when soil temperatures at a 1- to 2-inch depth exceed 55 degrees for four consecutive days).
For existing weeds, determine if you need chemical intervention or if regular mowing will suffice. Many winter annual weeds naturally die off when temperatures rise in May. If you must spray, apply post-emergent herbicides in March or April while weeds are small and actively growing.
Weeds to watch out for in Knoxville:
- Crabgrass (late February to Mid-March): Germinates in warm soil. Apply pre-emergent preventer now before dogwoods bloom, because once crabgrass sprouts in summer, it becomes much harder to control efficiently.
- Wild garlic and onion (February to March): These perennial weeds smell like onions when mowed. Apply post-emergent herbicides containing 2,4-D now, or wait until late fall for more effective root control.
- Henbit and chickweed (March to April): These winter annual weeds bloom purple or white in spring. Mowing usually manages them until they die in May heat, so skip the herbicides.
Good to know: Always verify the product is safe for your specific grass, as chemicals safe for Zoysia might damage fescue.
Warning: Do not apply “weed and feed” products containing pre-emergents if you plan to seed your fescue lawn this spring. The herbicide barrier that stops crabgrass will also prevent your new grass seed from germinating.
7. Check sprinklers and start watering
Check your sprinkler system in late April, once the threat of freezing temperatures has passed. Run a test cycle to identify leaks, broken heads, or misaligned nozzles before the summer heat arrives.
Knoxville usually receives ample spring rainfall (averaging around 4 inches monthly), so active irrigation is rarely needed before May. Wait to water until your lawn shows clear signs of thirst, such as a bluish-gray tint or footprints that remain visible in the grass after walking.
When you do water, aim for 1 to 1.5 inches per week total, combining rainfall and irrigation.
Good to know: Install or check your rain sensor now. This simple device ensures your sprinklers won’t run during our frequent spring showers, saving you money and preventing waterlogged turf.
Read more: How to Adjust Sprinkler Heads
8. Know when to mow
Many Knoxville homeowners start mowing too early. Don’t do this. Wait until your grass is actively growing and the ground is firm. Mowing wet turf on our soft red clay compacts the soil and tears out shallow roots.
Cool-season lawns usually wake up in March, while warm-season varieties often stay dormant until late April or May. Wait until the grass is tall enough to cut without removing more than one-third of the blade:
- Tall Fescue (a cool-season grass): Greens up in March. Start mowing when it reaches 3 to 4.5 inches, cutting it back to 2 to 3 inches.
- Bermuda (a warm-season grass): Greens up in late April. In mid-March, remove dead grass to help the soil warm up (vertical mowing or dethatching is best). Once green, maintain at 1 to 1.5 inches.
- Zoysia (a warm-season grass): Greens up in late April. Once green, maintain at 1.5 inches or higher.
Warning: Mow only when your grass is dry (not wet) to prevent clogging your mower and rutting the soil.
Good to know: Leave your grass clippings on the lawn. Grass clippings act as natural fertilizer, returning nitrogen to the soil as they decompose.
Read more: 6 Best Grass Types in Knoxville
9. Dethatch, if necessary
Thatch is a layer of dead grass and living shoots woven together. While a thin layer benefits your lawn, buildup exceeding one-half inch acts like a barrier, preventing water, oxygen, and fertilizer from reaching the soil.
To fix this, you need to break up that layer. You can use a thatch rake for small spots or rent a machine called a power rake to pull up the dead debris.
- Warm-season grasses (bermuda, Zoysia): Wait until May or June to dethatch. Your grass must be green and actively growing to ensure it recovers quickly in the rising temperatures.
- Cool-season grasses (tall fescue): The ideal time to dethatch fescue is early fall. However, if thatch is impenetrable in March, you can lightly rake it now, but avoid deep power raking before summer to prevent heat stress damage.
Read more: How to Dethatch Your Lawn
10. Wait to aerate
Our heavy soil hardens significantly after winter rains, creating a barrier that stops water and nutrients from reaching the grass root zone. Aeration fixes this by removing small plugs of soil to restore airflow.
However, aeration temporarily stresses your grass and exposes soil to weed seeds, so you must never aerate dormant turf. You should aerate only when your specific grass type is growing vigorously enough to “heal” the holes quickly, preventing weeds from taking over the gaps.
- Warm-season grasses: Wait until late May through July when the grass is green. Aerating during peak growth ensures the turf recovers quickly before summer heat stress.
- Cool-season grasses: Fall is the gold standard for aeration and overseeding. Aerate in March only if compaction is severe, acknowledging that open soil invites aggressive spring weeds.
Read More: When to Aerate Your Lawn in Tennessee
11. Overseed, if necessary
Keeping a luscious, green lawn in the transition zone isn’t an easy feat. If your turf is a warm-season grass type and looks like it can use a boost, go ahead and overseed your lawn in the spring.
If your lawn has a few bare or thinning patches, check that a lawn pest isn’t to blame before trying to overseed.
- Warm-season grass types: Wait until late May or June when soil temperatures reach 70 degrees or higher. Since residential varieties establish poorly from seed, using sod or plugs is usually the most effective choice.
- Cool-season grasses (tall fescue): Fall is the best time to aerate, but you can spot-seed in March when the soil hits 50 degrees Just know that spring seedlings are weak and may struggle during summer heat.
Read more: Fall Lawn Care Checklist for Knoxville
12. Fertilize, if needed
After getting the results of your soil test, you’ll know which fertilizer or soil amendments will be best for your turf. But whether or not you should fertilize in the spring depends on your grass type.
As a general rule:
- Fertilize warm-season grasses: Wait until May when the grass is fully green and soil temperatures consistently reach 65 degrees. Fertilizing too early feeds weeds and wastes money on dormant turf.
- Fertilize cool-season grasses: Fall is the best time to fertilize, but you can apply a light treatment in March if your lawn looks pale and soil temperatures reach 50 to 60 degrees.
Choose a fertilizer with slow-release nitrogen (like coated urea) to feed grass steadily without surge growth. Check here for the complete guide on how to fertilize your lawn.
Good to know: While Knoxville has no seasonal fertilizer bans, local stormwater guidelines require you to sweep stray granules off hard surfaces to prevent water pollution.
Read more: When to Fertilize Your Lawn in Tennessee
Sound like too much work? Hire a Lawn Love lawn care pro
Having a knock-out lawn in Knoxville isn’t impossible; it just takes some time and preparation. If you get your lawn going strong early in spring, you’ll have less to worry about in later months, giving you more time to stop and smell the roses.
If you want a stunning lawn without the headache, let Lawn Love help. Our Knoxville lawn care pros make it easy to handle all your lawn care needs.
Read next:
When to Plant Grass in Tennessee
Month-to-Month Tennessee Lawn Care Schedule
Main Image: Lawn mowed by a Lawn Love pro in Knoxville, TN. Illustration by Amy Stenglein / Lawn Love
Related Posts:
