Nashville
Apply ASAP63°F↓ cooling
Soil has cooled to 75°F, so winter weeds are sprouting. Pre-emergent still stops later flushes.
Winter weeds are sprouting now
Tennessee Weed Watch · updated Nov 3, 1:18 AM CT
When to apply pre-emergent in Tennessee
Live soil temperatures for Nashville, Memphis, Knoxville and Chattanooga, updated every three hours. Weeds sprout by soil temperature, not by the calendar, so the right week moves from year to year.
Tennessee lawns get pre-emergent twice a year: in spring for crabgrass and other summer weeds, and in fall for winter weeds.
Spring pre-emergentNext season
Typically Feb 16 – Mar 26
Stops crabgrass and other summer weeds before they sprout.
Fall pre-emergentThis season
Typically by Sep 3 – Sep 11
Stops winter weeds (annual bluegrass, henbit, chickweed) before they sprout.
Skip it if you are overseeding this fall.
Right now · fall pre-emergent season
Winter weeds are germinating — apply now if you haven't across Tennessee
Soil is 60–68°F now. They keep coming up in flushes into winter, so pre-emergent still helps. Overseeding this fall? Skip pre-emergent — it stops grass seed too.
Soil temperature by city
Soil 2 inches down, 5-day average: solid line = the last two weeks, dashed = the six-day forecast. Shaded = below 75°F, where winter weeds sprout — pre-emergent has to be down before the line gets there.
Memphis
Apply ASAP68°F↓ cooling
Soil has cooled to 75°F, so winter weeds are sprouting. Pre-emergent still stops later flushes.
Winter weeds are sprouting now
Knoxville
Apply ASAP60°F→ steady
Soil has cooled to 75°F, so winter weeds are sprouting. Pre-emergent still stops later flushes.
Winter weeds are sprouting now
Chattanooga
Apply ASAP61°F→ steady
Soil has cooled to 75°F, so winter weeds are sprouting. Pre-emergent still stops later flushes.
Winter weeds are sprouting now
Tennessee pre-emergent calendar
Spring pre-emergent stops crabgrass. The window runs from the typical day soil warms to 50°F to the day it holds 55°F, when crabgrass starts germinating (2016–2025). Fall pre-emergent stops winter weeds: have it down a week before soil usually cools to 75°F, when they start germinating.
| City | Spring pre-emergent (crabgrass) | Fall pre-emergent (winter weeds) |
|---|---|---|
| Nashville | Mar 7 – Mar 26 | Apply by Sep 5 |
| Memphis | Feb 18 – Mar 9 | Apply by Sep 4 |
| Knoxville | Mar 7 – Mar 25 | Apply by Sep 3 |
| Chattanooga | Feb 16 – Mar 15 | Apply by Sep 11 |
These are typical-year dates (the median of 2016–2025); any one year can run a couple of weeks earlier or later, which is what the live readings above are for. For your exact yard, check soil temperature by ZIP.
Recommended gear
Fall pre-emergents
Granular or liquid. Follow the label rate, and water it in.
Paid links. As an Amazon Associate, MeasureLawn earns from qualifying purchases.
Amazon
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Scotts Halts Crabgrass & Grassy Weed Preventer
Beginner friendlyPendimethalingranularcovers ~5,000 sq ft / 0.11 ac$24.97as of Nov 2, 10:00 AM UTC · may change
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The Andersons Barricade Professional-Grade Granular
Beginner friendly0.48% Prodiaminegranularcovers ~12,880 sq ft / 0.30 ac$79.88as of Nov 2, 10:00 AM UTC · may change
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Dimension 2EW (Dithiopyr)
Liquid concentrate; 64 oz half gallon; mix with water and spray
Dithiopyrliquidcovers ~91,428 sq ft / 2.1 ac$158.00as of Nov 2, 10:00 AM UTC · may change
What people in Tennessee are identifying
We record the state each identification comes from. Tennessee's list appears here once it has at least 40 identifications spread over 7 or more days — so no single scan stands out. Until then, see the national list, or add yours:
Identify a weed from a photoWeeds to watch in Tennessee this fall
Questions about Tennessee
When should I apply crabgrass pre-emergent in Tennessee?
Put crabgrass pre-emergent down as soil warms to 50°F, before it holds 55°F and crabgrass starts germinating. In a typical year (2016–2025) that window is Mar 7 – Mar 26 in Nashville; Feb 18 – Mar 9 in Memphis; Mar 7 – Mar 25 in Knoxville; Feb 16 – Mar 15 in Chattanooga.
When should I apply fall pre-emergent in Tennessee?
Winter weeds such as annual bluegrass, henbit and chickweed start germinating as soil cools to about 75°F in late summer and fall, and most come up once it is below 70°F. Have fall pre-emergent down before they start: typically by Sep 5 in Nashville; by Sep 4 in Memphis; by Sep 3 in Knoxville; by Sep 11 in Chattanooga. Skip it if you are overseeding this fall, because it stops grass seed too.
What is the soil temperature in Tennessee right now?
As of Nov 3, 1:18 AM CT: Nashville 63°F, Memphis 68°F, Knoxville 60°F, Chattanooga 61°F (5-day average, about 2.4 inches down). Winter weeds are germinating — apply now if you haven't across Tennessee.
How the readings and dates are made, and their limits: Weed Watch method. Soil data: Open-Meteo.com (CC BY 4.0); typical dates: NASA POWER.