Portland, OR planting zone & frost dates
Portland is in USDA hardiness zone 9a. The last spring frost usually comes around February 25 and the first fall frost around December 1, for a growing season of about 280 days.
Planting calendar for Portland
Dates are counted from the average last spring frost (February 25) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Dec 31 – Jan 14 Transplant outdoors: Mar 4 – Mar 11 |
| Peppers | Start seeds indoors: Dec 17 – Dec 31 Transplant outdoors: Mar 11 – Mar 18 |
| Eggplant | Start seeds indoors: Dec 17 – Dec 31 Transplant outdoors: Mar 11 – Mar 18 |
| Broccoli | Start seeds indoors: Dec 17 – Dec 31 Transplant outdoors: Jan 28 – Feb 11 |
| Cabbage | Start seeds indoors: Dec 17 – Dec 31 Transplant outdoors: Jan 28 – Feb 11 |
| Onions (sets) | Plant outdoors: Jan 28 – Feb 11 |
| Peas | Sow outdoors: Jan 14 – Jan 28 |
| Spinach | Sow outdoors: Jan 14 – Jan 28 |
| Lettuce | Sow outdoors: Jan 28 – Feb 11 |
| Carrots | Sow outdoors: Jan 28 – Feb 11 |
| Potatoes | Plant outdoors: Jan 28 – Feb 11 |
| Beans | Sow outdoors: Mar 4 – Mar 11 |
| Sweet corn | Sow outdoors: Mar 4 – Mar 11 |
| Cucumbers | Sow outdoors: Mar 4 – Mar 11 |
| Squash & zucchini | Sow outdoors: Mar 4 – Mar 11 |
| Basil | Start seeds indoors: Jan 14 – Jan 28 Transplant outdoors: Mar 4 – Mar 11 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 6 (8 weeks before the average first fall frost on Dec 1).
Useful for zone 9a gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Shade cloth — for hot summers
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Jan 24 | Feb 25 | Mar 21 |
| First 32°F frost in fall is before | Dec 27 | Dec 1 | Nov 10 |
How to read it: in spring there is a 10% chance of a frost after March 21, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 10. A hard freeze (28°F) usually ends around January 31.
Hardiness zone by ZIP code in Portland
- 97201 zone 8b
- 97202 zone 9a
- 97203 zone 9a
- 97204 zone 9a
- 97205 zone 8b
- 97206 zone 9a
- 97207 zone 9a
- 97208 zone 9a
- 97209 zone 9a
- 97210 zone 8b
- 97211 zone 9a
- 97212 zone 8b
- 97213 zone 8b
- 97214 zone 9a
- 97215 zone 9a
- 97216 zone 9a
- 97217 zone 9a
- 97218 zone 9a
- 97219 zone 8b
- 97220 zone 9a
- 97221 zone 8b
- 97222 zone 9a
- 97223 zone 9a
- 97224 zone 9a
- 97225 zone 8b
- 97227 zone 9a
- 97228 zone 9a
- 97229 zone 8b
- 97230 zone 9a
- 97231 zone 8b
- 97232 zone 9a
- 97233 zone 9a
- 97236 zone 9a
- 97238 zone 9a
- 97239 zone 8b
- 97240 zone 9a
- 97242 zone 9a
- 97250 zone 9a
- 97251 zone 9a
- 97252 zone 9a
- 97253 zone 9a
- 97254 zone 9a
- 97256 zone 9a
- 97266 zone 9a
- 97267 zone 9a
- 97268 zone 9a
- 97269 zone 9a
- 97280 zone 8b
- 97281 zone 9a
- 97282 zone 9a
- 97283 zone 8b
- 97286 zone 9a
- 97290 zone 9a
- 97291 zone 8b
- 97292 zone 9a
- 97293 zone 9a
- 97294 zone 9a
- 97296 zone 9a
- 97298 zone 8b
Nearby cities
- Milwaukie zone 9a, last frost Feb 25
- Lake Oswego zone 9a, last frost Mar 18
- Oak Grove zone 9a, last frost Mar 18
- Beaverton zone 9a, last frost Feb 11
- Tigard zone 9a, last frost Apr 1
- Oatfield zone 9a, last frost Mar 18
- Cedar Mill zone 8b, last frost Feb 11
- Gladstone zone 9a, last frost Mar 18
Questions
What growing zone is Portland, OR?
Portland is in USDA Plant Hardiness Zone 9a (average extreme winter low 20°F to 25°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 8b.
When is the last frost in Portland?
The average last spring frost (32°F) in Portland is February 25. There is still a 10% chance of frost until March 21.
When can I plant tomatoes in Portland?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Mar 4 – Mar 11. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Portland Kgw-Tv, OR (USC00356749), 1.2 km (0.7 mi) from the city center, elevation 48 m, based on 24 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.