Kansas City
Apply ASAP66°F↓ cooling
Soil has cooled to 75°F, so winter weeds are sprouting. Pre-emergent still stops later flushes.
Winter weeds are sprouting now
Missouri Weed Watch · updated Nov 3, 1:18 AM CT
When to apply pre-emergent in Missouri
Live soil temperatures for Kansas City, St. Louis and Springfield, updated every three hours. Weeds sprout by soil temperature, not by the calendar, so the right week moves from year to year.
Missouri 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 Mar 15 – Apr 9
Stops crabgrass and other summer weeds before they sprout.
Fall pre-emergentThis season
Typically by Aug 15 – Aug 31
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: Kansas City. Winter weeds are up — spot-treat: St. Louis and Springfield
Soil is 65–66°F now. Spot-treat them with a post-emergent on a mild day, or in early spring before they flower.
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.
St. Louis
Spot-treat65°F↓ cooling
Winter weeds are up. Spot-treat them on a mild day, or in early spring before they flower.
Winter weeds are up
Springfield
Spot-treat65°F↓ cooling
Winter weeds are up. Spot-treat them on a mild day, or in early spring before they flower.
Winter weeds are up
Missouri 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) |
|---|---|---|
| Kansas City | Mar 22 – Apr 9 | Apply by Aug 31 |
| St. Louis | Mar 22 – Apr 7 | Apply by Aug 19 |
| Springfield | Mar 15 – Apr 9 | Apply by Aug 15 |
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 Missouri are identifying
We record the state each identification comes from. Missouri'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 Missouri this fall
Questions about Missouri
When should I apply crabgrass pre-emergent in Missouri?
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 22 – Apr 9 in Kansas City; Mar 22 – Apr 7 in St. Louis; Mar 15 – Apr 9 in Springfield.
When should I apply fall pre-emergent in Missouri?
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 Aug 31 in Kansas City; by Aug 19 in St. Louis; by Aug 15 in Springfield. Skip it if you are overseeding this fall, because it stops grass seed too.
What is the soil temperature in Missouri right now?
As of Nov 3, 1:18 AM CT: Kansas City 66°F, St. Louis 65°F, Springfield 65°F (5-day average, about 2.4 inches down). Winter weeds are germinating — apply now if you haven't: Kansas City. Winter weeds are up — spot-treat: St. Louis and Springfield.
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.