St. Louis, MO Lawn Care Calendar
In a typical year, put down crabgrass preventer in St. Louis between Mar 15 and Apr 16. The best time to overseed is between Aug 19 and Oct 8. The last spring frost usually comes around Apr 9. Most lawns here are cool-season grass (tall fescue, Kentucky bluegrass, ryegrass).
Typical lawn care dates in St. Louis
| Task | Typical window |
|---|---|
| Crabgrass preventer (pre-emergent)Crabgrass sprouts once soil stays above 55°F. Apply when soil reaches 50°F, before that happens. | Mar 15 – Apr 16 |
| Spring fertilizerA light feeding once soil warms past 55°F and the grass is actively growing. | Apr 9 – May 14 |
| Overseeding & seedingLate summer to early fall: seedlings need about 6–10 weeks of growth before the first frost. | Aug 19 – Oct 8 |
| Fall fertilizerThe most important feeding for cool-season grass, from early fall until soil cools to about 45°F. | Sep 24 – Nov 25 |
Median dates, 2016–2025, from NOAA weather data for St. Louis. This year's dates can differ by a few weeks.
Month-by-month lawn care in St. Louis
- JanuaryNo treatments due; mow as needed.
- FebruaryNo treatments due; mow as needed.
- MarchCrabgrass preventer (pre-emergent)
- AprilCrabgrass preventer (pre-emergent)Spring fertilizer
- MaySpring fertilizer
- JuneNo treatments due; mow as needed.
- JulyNo treatments due; mow as needed.
- AugustOverseeding & seeding
- SeptemberOverseeding & seedingFall fertilizer
- OctoberOverseeding & seedingFall fertilizer
- NovemberFall fertilizer
- DecemberNo treatments due; mow as needed.
Soil temperature in St. Louis by month
Average soil temperature 4 inches down, estimated from 2016–2025 weather. It bottoms out in January at 33°F and peaks in July at 81°F. Crabgrass preventer goes down when it reaches 50°F, usually around Mar 15.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 33°F | 36°F | 47°F | 56°F | 67°F | 77°F | 81°F | 78°F | 74°F | 62°F | 47°F | 39°F |
St. Louis lawn timing, year by year
Over the last 10 years, soil in St. Louis reached 50°F, the signal for crabgrass preventer, as early as Feb 18 (2017) and as late as Apr 22 (2018): 63 days apart. A fixed calendar date can't follow that, which is why the report above uses this year's soil temperature. Between the typical last spring frost (Apr 9) and first fall frost (Nov 2), the growing season lasts about 207 days.
| Year | Crabgrass window opened | Last spring frost | First fall frost |
|---|---|---|---|
| 2025 | Mar 12 | Apr 8 | Nov 10 |
| 2024 | Mar 4 | Mar 20 | Nov 26 |
| 2023 | Apr 1 | Mar 29 | Oct 31 |
| 2022 | Mar 17 | Mar 28 | Oct 19 |
| 2021 | Mar 9 | Apr 21 | Nov 4 |
| 2020 | Mar 27 | Apr 18 | Nov 2 |
| 2019 | Apr 5 | Apr 15 | Oct 31 |
| 2018 | Apr 22 | Apr 17 | Oct 21 |
| 2017 | Feb 18 | Mar 17 | Oct 30 |
| 2016 | Mar 9 | Apr 9 | Nov 20 |
Estimated from daily temperatures for St. Louis. A dash means it didn't happen that year.
Frequently asked questions
When should I apply pre-emergent in St. Louis?
In a typical year, between Mar 15 and Apr 16. Put it down when soil reaches 50°F, before it stays above 55°F and crabgrass starts sprouting. Early springs move this up by a week or more, so check this year's soil temperature above.
When is the best time to plant grass seed in St. Louis?
Early fall, typically Aug 19 – Oct 8, while soil cools from 65°F toward 50°F.
When is the last frost in St. Louis?
The median last spring frost is Apr 9 and the median first fall frost is Nov 2 (2016–2025).
How long is the growing season in St. Louis?
About 207 days, from the median last spring frost on Apr 9 to the median first fall frost on Nov 2 (2016–2025).
Lawn care guides
More Missouri lawn calendars
Nearby cities in other states
- Carbondale, IL 82 miles away · crabgrass preventer Mar 20 – Apr 16
- Springfield, IL 85 miles away · crabgrass preventer Apr 8 – Apr 24
- Paducah, KY 138 miles away · crabgrass preventer Mar 11 – Apr 4
- Peoria, IL 146 miles away · crabgrass preventer Apr 10 – Apr 25