Kennewick, WA Lawn Care Calendar
In a typical year, put down crabgrass preventer in Kennewick between Mar 31 and May 3. The best time to overseed is between Aug 22 and Oct 11. The last spring frost usually comes around Mar 21. Most lawns here are cool-season grass (tall fescue, Kentucky bluegrass, ryegrass).
Typical lawn care dates in Kennewick
| 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 31 – May 3 |
| Spring fertilizerA light feeding once soil warms past 55°F and the grass is actively growing. | Apr 26 – May 31 |
| Overseeding & seedingLate summer to early fall: seedlings need about 6–10 weeks of growth before the first frost. | Aug 22 – Oct 11 |
| Fall fertilizerThe most important feeding for cool-season grass, from early fall until soil cools to about 45°F. | Sep 11 – Nov 10 |
Median dates, 2016–2025, from NOAA weather data for Kennewick. This year's dates can differ by a few weeks.
Month-by-month lawn care in Kennewick
- JanuaryNo treatments due; mow as needed.
- FebruaryNo treatments due; mow as needed.
- MarchCrabgrass preventer (pre-emergent)
- AprilCrabgrass preventer (pre-emergent)Spring fertilizer
- MayCrabgrass preventer (pre-emergent)Spring 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 Kennewick by month
Average soil temperature 4 inches down, estimated from 2016–2025 weather. It bottoms out in January at 35°F and peaks in July at 78°F. Crabgrass preventer goes down when it reaches 50°F, usually around Mar 31.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 35°F | 38°F | 46°F | 54°F | 63°F | 70°F | 78°F | 77°F | 68°F | 56°F | 44°F | 37°F |
Kennewick lawn timing, year by year
Over the last 10 years, soil in Kennewick reached 50°F, the signal for crabgrass preventer, as early as Feb 16 (2016) and as late as Apr 8 (2023): 51 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 (Mar 21) and first fall frost (Nov 5), the growing season lasts about 229 days.
| Year | Crabgrass window opened | Last spring frost | First fall frost |
|---|---|---|---|
| 2025 | Mar 24 | Mar 7 | Nov 20 |
| 2024 | Mar 18 | Mar 16 | Oct 31 |
| 2023 | Apr 8 | Mar 28 | Oct 28 |
| 2022 | Mar 23 | Mar 11 | Nov 10 |
| 2021 | Apr 2 | Apr 13 | Nov 17 |
| 2020 | Apr 8 | Apr 14 | Oct 23 |
| 2019 | Apr 1 | Mar 21 | Oct 10 |
| 2018 | Apr 7 | Mar 24 | Nov 8 |
| 2017 | Mar 29 | Feb 26 | Oct 31 |
| 2016 | Feb 16 | Mar 19 | Nov 18 |
Estimated from daily temperatures for Kennewick. A dash means it didn't happen that year.
Frequently asked questions
When should I apply pre-emergent in Kennewick?
In a typical year, between Mar 31 and May 3. 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 Kennewick?
Early fall, typically Aug 22 – Oct 11, while soil cools from 65°F toward 50°F.
When is the last frost in Kennewick?
The median last spring frost is Mar 21 and the median first fall frost is Nov 5 (2016–2025).
How long is the growing season in Kennewick?
About 229 days, from the median last spring frost on Mar 21 to the median first fall frost on Nov 5 (2016–2025).
Lawn care guides
More Washington lawn calendars
Nearby cities in other states
- Coeur d'Alene, ID 151 miles away · crabgrass preventer Apr 27 – May 18
- Portland, OR 177 miles away · crabgrass preventer Apr 1 – May 5
- Bend, OR 182 miles away · crabgrass preventer May 7 – Jun 4
- Salem, OR 208 miles away · crabgrass preventer Apr 1 – May 9