Headworks Portland Wtr B, OR Frost Dates & Growing Season

The two dates every Headworks Portland Wtr B garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Mar 27
~50% chance of frost after
First fall frost
Nov 18
~50% chance of frost before
Growing season
236 days
frost-free stretch
USDA zone
≈ 9a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Feb 26 Mar 27 Apr 20
First fall frost Dec 10 Nov 18 Oct 26
Hard freeze (28°F), median last Feb 14 · first Dec 9

Computed from NOAA 1991–2020 climate normals at the HEADWORKS PORTLAND WTR B station. "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Headworks Portland Wtr B

Computed from Headworks Portland Wtr B's own frost dates. Click any crop for the full zone-9 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Jan 30 – Feb 13 Apr 3 – Apr 10
🫑 Peppers Jan 16 – Jan 30 Apr 10 – Apr 17
🥬 Lettuce Feb 13 – Feb 27 Feb 27 – Mar 13 Feb 27 – Mar 27
🫛 Peas Feb 13 – Feb 27
🥕 Carrots Mar 6 – Mar 27
🥦 Broccoli Feb 6 – Feb 20 Mar 6 – Mar 20
🥬 Kale Feb 13 – Feb 27 Feb 27 – Mar 13 Feb 27 – Mar 13
🥒 Cucumbers Feb 27 – Mar 6 Apr 3 – Apr 10 Apr 3 – Apr 10
🥒 Zucchini Feb 27 – Mar 6 Apr 3 – Apr 10 Apr 3 – Apr 10
🫘 Green Beans (Bush) Apr 3 – Apr 10
🌽 Sweet Corn Apr 3 – Apr 10
🌿 Basil Feb 13 – Feb 27 Apr 3 – Apr 10 Apr 10 – Apr 17
🧄 Garlic Fall: Oct 7 – Nov 4

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Headworks Portland Wtr B's dates automatically after a lookup.

Reading the season in Headworks Portland Wtr B

With roughly 236 frost-free days, Headworks Portland Wtr B gardens fit long-season crops — melons, winter squash, sweet potatoes — with room left for spring and fall rounds of greens and roots. The first frost around Nov 18 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Headworks Portland Wtr B, OR?

The average last spring frost in Headworks Portland Wtr B is around Mar 27, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Headworks Portland Wtr B, OR?

The average first fall frost in Headworks Portland Wtr B arrives around Nov 18. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Headworks Portland Wtr B?

About 236 frost-free days on average, from Mar 27 to Nov 18. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Headworks Portland Wtr B in?

USDA zone 9a on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.