Woodburn, OR planting zone & frost dates

Woodburn is in USDA hardiness zone 8b. The last spring frost usually comes around March 16 and the first fall frost around November 14, for a growing season of about 242 days.

USDA hardiness zone8bavg. extreme winter low 15°F to 20°F
Average last spring frostMarch 1690% chance of no frost after April 7
Average first fall frostNovember 1410% chance of frost by October 27
Growing season242 daysfrost-free days in an average year

Planting calendar for Woodburn

Dates are counted from the average last spring frost (March 16) 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.

CropWhen
TomatoesStart seeds indoors: Jan 19 – Feb 2
Transplant outdoors: Mar 23 – Mar 30
PeppersStart seeds indoors: Jan 5 – Jan 19
Transplant outdoors: Mar 30 – Apr 6
EggplantStart seeds indoors: Jan 5 – Jan 19
Transplant outdoors: Mar 30 – Apr 6
BroccoliStart seeds indoors: Jan 5 – Jan 19
Transplant outdoors: Feb 16 – Mar 2
CabbageStart seeds indoors: Jan 5 – Jan 19
Transplant outdoors: Feb 16 – Mar 2
Onions (sets)Plant outdoors: Feb 16 – Mar 2
PeasSow outdoors: Feb 2 – Feb 16
SpinachSow outdoors: Feb 2 – Feb 16
LettuceSow outdoors: Feb 16 – Mar 2
CarrotsSow outdoors: Feb 16 – Mar 2
PotatoesPlant outdoors: Feb 16 – Mar 2
BeansSow outdoors: Mar 23 – Mar 30
Sweet cornSow outdoors: Mar 23 – Mar 30
CucumbersSow outdoors: Mar 23 – Mar 30
Squash & zucchiniSow outdoors: Mar 23 – Mar 30
BasilStart seeds indoors: Feb 2 – Feb 16
Transplant outdoors: Mar 23 – Mar 30

Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 19 (8 weeks before the average first fall frost on Nov 14).

Useful for zone 8b gardens

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Frost risk in detail

90% chance50% chance10% chance
Last 32°F frost in spring is afterFeb 21Mar 16Apr 7
First 32°F frost in fall is beforeDec 6Nov 14Oct 27

How to read it: in spring there is a 10% chance of a frost after April 7, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 27. A hard freeze (28°F) usually ends around February 15.

Hardiness zone by ZIP code in Woodburn

Nearby cities

All cities in Oregon → · Other zone 8b cities →

Questions

What growing zone is Woodburn, OR?

Woodburn is in USDA Plant Hardiness Zone 8b (average extreme winter low 15°F to 20°F), according to the USDA 2023 map.

When is the last frost in Woodburn?

The average last spring frost (32°F) in Woodburn is March 16. There is still a 10% chance of frost until April 7.

When can I plant tomatoes in Woodburn?

Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Mar 23 – Mar 30. Start seeds indoors 6–8 weeks before the last frost.

Frost dates: NOAA U.S. Climate Normals 1991–2020, station Aurora State Ap, OR (USW00094281), 13.5 km (8.4 mi) from the city center, elevation 60 m, based on 23 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.