Casper, WY Lawn Care Calendar
In a typical year, put down crabgrass preventer in Casper between May 12 and May 29. The best time to overseed is between Jul 22 and Sep 10. The last spring frost usually comes around May 11. Most lawns here are cool-season grass (tall fescue, Kentucky bluegrass, ryegrass).
Typical lawn care dates in Casper
| Task | Typical window |
|---|---|
| Crabgrass preventer (pre-emergent)Crabgrass sprouts once soil stays above 55°F. Apply when soil reaches 50°F, before that happens. | May 12 – May 29 |
| Spring fertilizerA light feeding once soil warms past 55°F and the grass is actively growing. | May 22 – Jun 26 |
| Overseeding & seedingLate summer to early fall: seedlings need about 6–10 weeks of growth before the first frost. | Jul 22 – Sep 10 |
| Fall fertilizerThe most important feeding for cool-season grass, from early fall until soil cools to about 45°F. | Aug 17 – Oct 26 |
Median dates, 2016–2025, from NOAA weather data for Casper. This year's dates can differ by a few weeks.
Month-by-month lawn care in Casper
- JanuaryNo treatments due; mow as needed.
- FebruaryNo treatments due; mow as needed.
- MarchNo treatments due; mow as needed.
- AprilNo treatments due; mow as needed.
- MayCrabgrass preventer (pre-emergent)Spring fertilizer
- JuneSpring fertilizer
- JulyOverseeding & seeding
- AugustOverseeding & seedingFall fertilizer
- SeptemberOverseeding & seedingFall fertilizer
- OctoberFall fertilizer
- NovemberNo treatments due; mow as needed.
- DecemberNo treatments due; mow as needed.
Soil temperature in Casper by month
Average soil temperature 4 inches down, estimated from 2016–2025 weather. It bottoms out in January at 26°F and peaks in July at 72°F. Crabgrass preventer goes down when it reaches 50°F, usually around May 12.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 26°F | 26°F | 36°F | 42°F | 52°F | 65°F | 72°F | 70°F | 62°F | 48°F | 38°F | 31°F |
Casper lawn timing, year by year
Over the last 10 years, soil in Casper reached 50°F, the signal for crabgrass preventer, as early as Apr 28 (2020) and as late as May 20 (2016): 22 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 (May 11) and first fall frost (Oct 5), the growing season lasts about 147 days.
| Year | Crabgrass window opened | Last spring frost | First fall frost |
|---|---|---|---|
| 2025 | May 9 | May 2 | Oct 7 |
| 2024 | May 13 | May 5 | Oct 1 |
| 2023 | May 3 | Apr 29 | Oct 13 |
| 2022 | May 15 | Jun 2 | Oct 16 |
| 2021 | May 15 | May 12 | Oct 12 |
| 2020 | Apr 28 | May 9 | Sep 8 |
| 2019 | May 14 | May 23 | Oct 3 |
| 2018 | May 5 | Apr 27 | Sep 26 |
| 2017 | May 6 | May 21 | Oct 3 |
| 2016 | May 20 | May 12 | Oct 7 |
Estimated from daily temperatures for Casper. A dash means it didn't happen that year.
Frequently asked questions
When should I apply pre-emergent in Casper?
In a typical year, between May 12 and May 29. 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 Casper?
Early fall, typically Jul 22 – Sep 10, while soil cools from 65°F toward 50°F.
When is the last frost in Casper?
The median last spring frost is May 11 and the median first fall frost is Oct 5 (2016–2025).
How long is the growing season in Casper?
About 147 days, from the median last spring frost on May 11 to the median first fall frost on Oct 5 (2016–2025).
Lawn care guides
More Wyoming lawn calendars
Nearby cities in other states
- Fort Collins, CO 170 miles away · crabgrass preventer Apr 21 – May 19
- Rapid City, SD 176 miles away · crabgrass preventer May 4 – May 23
- Greeley, CO 188 miles away · crabgrass preventer Apr 23 – May 17
- Boulder, CO 205 miles away · crabgrass preventer Apr 13 – May 17