When to plant in Gladstone, OR
USDA Zone 9aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Gladstone, Oregon — all computed from Gladstone's nearest NOAA weather station.
Gladstone enjoys a long ~245-day frost-free season — you can succession-sow, fit in a second crop, and grow long-season heat-lovers with room to spare. In zone 9a, frost is a minor factor for Gladstone — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
OREGON CITY · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Gladstone’s own odds, recorded at OREGON CITY.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 4 | Apr 15 | Mar 26 | Oct 16 | Oct 31 | Nov 20 |
| 32°F | Apr 11 | Mar 18 | Feb 19 | Oct 30 | Nov 18 | Dec 12 |
| 28°F | Mar 7 | Feb 12 | Jan 1 | Nov 16 | Dec 8 | Jan 5 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Gladstone, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 17 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Gladstone planting FAQ
When is the last spring frost in Gladstone, OR?
On average, the last spring frost in Gladstone is around March 18 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Gladstone, OR?
Expect Gladstone's first fall frost near November 18 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Gladstone in?
Gladstone is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Gladstone?
Gladstone has about 245 frost-free days — a long growing season — between the average last spring frost (March 18) and first fall frost (November 18).
When should I plant tomatoes in Gladstone?
For Gladstone, sow tomatoes indoors about January 21–February 4 and move the seedlings out around March 25, after the last spring frost.
Never miss a window in Gladstone
An email when it’s time to start seeds, transplant, and sow — timed to Gladstone’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Oatfield · 3 km
- West Linn · 4 km
- Oak Grove · 4 km
- Oregon City · 5 km
- Milwaukie · 7 km
- Happy Valley · 8 km
- Lake Oswego · 9 km
- Damascus · 13 km
Frost dates recorded at OREGON CITY, 3 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Gladstone, OR — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00356334. Retrieved from https://blissgarden.com/oregon/gladstone.