Iowa City, IA Lawn Care Calendar
In a typical year, put down crabgrass preventer in Iowa City between Apr 16 and Apr 30. The best time to overseed is between Aug 5 and Sep 24. The last spring frost usually comes around Apr 24. Most lawns here are cool-season grass (tall fescue, Kentucky bluegrass, ryegrass).
Typical lawn care dates in Iowa City
| 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 16 – Apr 30 |
| Spring fertilizerA light feeding once soil warms past 55°F and the grass is actively growing. | Apr 23 – May 28 |
| Overseeding & seedingLate summer to early fall: seedlings need about 6–10 weeks of growth before the first frost. | Aug 5 – Sep 24 |
| Fall fertilizerThe most important feeding for cool-season grass, from early fall until soil cools to about 45°F. | Sep 1 – Nov 1 |
Median dates, 2016–2025, from NOAA weather data for Iowa City. This year's dates can differ by a few weeks.
Month-by-month lawn care in Iowa City
- JanuaryNo treatments due; mow as needed.
- FebruaryNo treatments due; mow as needed.
- MarchNo treatments due; mow as needed.
- 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
- OctoberFall fertilizer
- NovemberFall fertilizer
- DecemberNo treatments due; mow as needed.
Soil temperature in Iowa City by month
Average soil temperature 4 inches down, estimated from 2016–2025 weather. It bottoms out in January at 22°F and peaks in July at 75°F. Crabgrass preventer goes down when it reaches 50°F, usually around Apr 16.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 22°F | 25°F | 39°F | 48°F | 61°F | 72°F | 75°F | 73°F | 68°F | 55°F | 40°F | 29°F |
Iowa City lawn timing, year by year
Over the last 10 years, soil in Iowa City reached 50°F, the signal for crabgrass preventer, as early as Apr 5 (2021) and as late as May 5 (2022): 30 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 24) and first fall frost (Oct 19), the growing season lasts about 178 days.
| Year | Crabgrass window opened | Last spring frost | First fall frost |
|---|---|---|---|
| 2025 | Apr 14 | Apr 9 | Oct 24 |
| 2024 | Apr 11 | Apr 22 | Oct 16 |
| 2023 | Apr 10 | Apr 24 | Oct 30 |
| 2022 | May 5 | Apr 27 | Oct 8 |
| 2021 | Apr 5 | Apr 22 | Oct 23 |
| 2020 | Apr 23 | May 12 | Oct 20 |
| 2019 | Apr 21 | Apr 28 | Oct 12 |
| 2018 | Apr 24 | Apr 29 | Oct 16 |
| 2017 | Apr 9 | Apr 7 | Oct 29 |
| 2016 | Apr 16 | Apr 13 | Oct 14 |
Estimated from daily temperatures for Iowa City. A dash means it didn't happen that year.
Frequently asked questions
When should I apply pre-emergent in Iowa City?
In a typical year, between Apr 16 and Apr 30. 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 Iowa City?
Early fall, typically Aug 5 – Sep 24, while soil cools from 65°F toward 50°F.
When is the last frost in Iowa City?
The median last spring frost is Apr 24 and the median first fall frost is Oct 19 (2016–2025).
How long is the growing season in Iowa City?
About 178 days, from the median last spring frost on Apr 24 to the median first fall frost on Oct 19 (2016–2025).
Lawn care guides
More Iowa lawn calendars
Nearby cities in other states
- Peoria, IL 121 miles away · crabgrass preventer Apr 10 – Apr 25
- Rockford, IL 132 miles away · crabgrass preventer Apr 19 – May 6
- Madison, WI 146 miles away · crabgrass preventer Apr 20 – May 16
- La Crosse, WI 149 miles away · crabgrass preventer Apr 20 – May 10