Denver, CO Lawn Care Calendar
In a typical year, put down crabgrass preventer in Denver between Apr 8 and May 11. The best time to overseed is between Jul 30 and Sep 18. The last spring frost usually comes around Apr 25. Most lawns here are cool-season grass (tall fescue, Kentucky bluegrass, ryegrass).
Typical lawn care dates in Denver
| Task | Typical window |
|---|---|
| Crabgrass preventer (pre-emergent)Crabgrass sprouts once soil stays above 55°F. Apply when soil reaches 50°F, before that happens. | Apr 8 – May 11 |
| Spring fertilizerA light feeding once soil warms past 55°F and the grass is actively growing. | May 4 – Jun 8 |
| Overseeding & seedingLate summer to early fall: seedlings need about 6–10 weeks of growth before the first frost. | Jul 30 – Sep 18 |
| Fall fertilizerThe most important feeding for cool-season grass, from early fall until soil cools to about 45°F. | Sep 11 – Nov 3 |
Median dates, 2016–2025, from NOAA weather data for Denver. This year's dates can differ by a few weeks.
Month-by-month lawn care in Denver
- JanuaryNo treatments due; mow as needed.
- FebruaryNo treatments due; mow as needed.
- MarchNo treatments due; mow as needed.
- AprilCrabgrass preventer (pre-emergent)
- MayCrabgrass preventer (pre-emergent)Spring fertilizer
- JuneSpring fertilizer
- JulyOverseeding & seeding
- AugustOverseeding & seeding
- SeptemberOverseeding & seedingFall fertilizer
- OctoberFall fertilizer
- NovemberFall fertilizer
- DecemberNo treatments due; mow as needed.
Soil temperature in Denver by month
Average soil temperature 4 inches down, estimated from 2016–2025 weather. It bottoms out in January at 32°F and peaks in July at 77°F. Crabgrass preventer goes down when it reaches 50°F, usually around Apr 8.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 32°F | 34°F | 42°F | 49°F | 57°F | 70°F | 77°F | 75°F | 68°F | 54°F | 44°F | 37°F |
Denver lawn timing, year by year
Over the last 10 years, soil in Denver reached 50°F, the signal for crabgrass preventer, as early as Mar 16 (2017) and as late as Apr 28 (2018): 43 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 25) and first fall frost (Oct 13), the growing season lasts about 171 days.
| Year | Crabgrass window opened | Last spring frost | First fall frost |
|---|---|---|---|
| 2025 | Mar 26 | Apr 21 | Oct 29 |
| 2024 | Apr 13 | Apr 21 | Oct 31 |
| 2023 | Apr 11 | Apr 24 | Oct 27 |
| 2022 | Apr 20 | May 22 | Oct 24 |
| 2021 | Apr 3 | Apr 24 | Oct 15 |
| 2020 | Apr 8 | Apr 18 | Sep 9 |
| 2019 | Apr 6 | May 21 | Oct 10 |
| 2018 | Apr 28 | Apr 26 | Oct 10 |
| 2017 | Mar 16 | May 20 | Oct 9 |
| 2016 | Apr 6 | May 8 | Oct 7 |
Estimated from daily temperatures for Denver. A dash means it didn't happen that year.
Frequently asked questions
When should I apply pre-emergent in Denver?
In a typical year, between Apr 8 and May 11. 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 Denver?
Early fall, typically Jul 30 – Sep 18, while soil cools from 65°F toward 50°F.
When is the last frost in Denver?
The median last spring frost is Apr 25 and the median first fall frost is Oct 13 (2016–2025).
How long is the growing season in Denver?
About 171 days, from the median last spring frost on Apr 25 to the median first fall frost on Oct 13 (2016–2025).
Lawn care guides
More Colorado lawn calendars
Nearby cities in other states
- Cheyenne, WY 97 miles away · crabgrass preventer May 12 – Jun 8
- Laramie, WY 113 miles away · crabgrass preventer May 20 – Jun 11
- Casper, WY 227 miles away · crabgrass preventer May 12 – May 29
- North Platte, NE 242 miles away · crabgrass preventer Apr 24 – May 14