Portland, OR Lawn Care Calendar
In a typical year, put down crabgrass preventer in Portland between Apr 1 and May 5. The best time to overseed is between Sep 11 and Oct 31. The last spring frost usually comes around Mar 9. Most lawns here are cool-season grass (tall fescue, Kentucky bluegrass, ryegrass).
Typical lawn care dates in Portland
| 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 1 – May 5 |
| Spring fertilizerA light feeding once soil warms past 55°F and the grass is actively growing. | Apr 28 – Jun 2 |
| Overseeding & seedingLate summer to early fall: seedlings need about 6–10 weeks of growth before the first frost. | Sep 11 – Oct 31 |
| Fall fertilizerThe most important feeding for cool-season grass, from early fall until soil cools to about 45°F. | Jul 21 – Nov 29 |
Median dates, 2016–2025, from NOAA weather data for Portland. This year's dates can differ by a few weeks.
Month-by-month lawn care in Portland
- JanuaryNo treatments due; mow as needed.
- FebruaryNo treatments due; mow as needed.
- MarchNo treatments due; mow as needed.
- AprilCrabgrass preventer (pre-emergent)Spring fertilizer
- MayCrabgrass preventer (pre-emergent)Spring fertilizer
- JuneSpring fertilizer
- JulyFall fertilizer
- AugustFall fertilizer
- SeptemberOverseeding & seedingFall fertilizer
- OctoberOverseeding & seedingFall fertilizer
- NovemberFall fertilizer
- DecemberNo treatments due; mow as needed.
Soil temperature in Portland by month
Average soil temperature 4 inches down, estimated from 2016–2025 weather. It bottoms out in January at 42°F and peaks in August at 71°F. Crabgrass preventer goes down when it reaches 50°F, usually around Apr 1.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 42°F | 43°F | 47°F | 52°F | 59°F | 64°F | 70°F | 71°F | 65°F | 56°F | 48°F | 43°F |
Portland lawn timing, year by year
Over the last 10 years, soil in Portland reached 50°F, the signal for crabgrass preventer, as early as Feb 15 (2016) and as late as Apr 23 (2023): 67 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 9) and first fall frost (Nov 25), the growing season lasts about 261 days.
| Year | Crabgrass window opened | Last spring frost | First fall frost |
|---|---|---|---|
| 2025 | Mar 25 | Feb 15 | — |
| 2024 | Mar 17 | Mar 9 | Dec 1 |
| 2023 | Apr 23 | Feb 26 | Nov 25 |
| 2022 | Mar 25 | Mar 13 | Nov 10 |
| 2021 | Apr 15 | Apr 12 | Dec 6 |
| 2020 | Apr 9 | Mar 13 | Oct 27 |
| 2019 | Mar 19 | Mar 12 | Oct 29 |
| 2018 | Apr 7 | Mar 7 | Nov 10 |
| 2017 | Apr 17 | Feb 4 | Dec 9 |
| 2016 | Feb 15 | Jan 5 | Dec 7 |
Estimated from daily temperatures for Portland. A dash means it didn't happen that year.
Frequently asked questions
When should I apply pre-emergent in Portland?
In a typical year, between Apr 1 and May 5. 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 Portland?
Early fall, typically Sep 11 – Oct 31, while soil cools from 65°F toward 50°F.
When is the last frost in Portland?
The median last spring frost is Mar 9 and the median first fall frost is Nov 25 (2016–2025).
How long is the growing season in Portland?
About 261 days, from the median last spring frost on Mar 9 to the median first fall frost on Nov 25 (2016–2025).
Lawn care guides
More Oregon lawn calendars
Nearby cities in other states
- Vancouver, WA 8 miles away · crabgrass preventer Apr 4 – May 9
- Tacoma, WA 120 miles away · crabgrass preventer Apr 17 – May 16
- Yakima, WA 128 miles away · crabgrass preventer Apr 18 – May 6
- Seattle, WA 145 miles away · crabgrass preventer Apr 5 – May 14