Climate-based cabbage planting guide for Seattle, Washington

When to Plant Cabbage in Seattle: Timing and Maturity Guide

Cabbage is usually straightforward to fit into the season in Seattle. Gardeners typically get more value from steady growth and timing than from worrying about whether the crop will finish.

Typical Planting Window

Excellent fit in this climate

Use the planting dates below for cabbage in Seattle.

Start indoors January 16
Typical planting window February 27 – March 13
Method Transplant
Typical days to maturity 70–90

Gardeners usually start indoors around January 16 and plant outdoors from about February 27. Most varieties need about 70–90 days to reach maturity once they are in the garden.

Cabbage is usually easy to fit into the season in Seattle, and the real payoff is having enough room to size the crop properly and harvest at the stage you actually want.

The climate usually makes this crop possible without strain, but the difference between an average result and a strong one still comes from steady growth and harvesting at the right stage.

Best local strategy: Take advantage of the margin by managing for even sizing and a clean finish, not by getting casual about timing.

Can Cabbage Mature in Seattle?

Growing degree days measure how much useful warmth typically accumulates during the season. For cabbage, this helps estimate whether local heat accumulation is usually enough for the crop to reach maturity on time.

Available GDD (base 40) 4787
Typical crop GDD target 1000
Heat margin +3787

From the usual planting window, Seattle typically provides about 4787 growing degree days for cabbage. With a typical crop target of 1000, that leaves a heat margin of +3787. That large heat margin means the crop usually has no trouble reaching maturity here. In practice, planting timing mostly affects how comfortably the crop sizes up and when harvest is ready, not whether the crop can finish.

GDD Checkpoints for Seattle

If planting later than usual, this table shows how much growing degree day heat is still available from each point in the season. For cabbage, it is most useful for judging how much freedom you still have to plant for quality, finish, and harvest goals as the season moves along.

Checkpoint Remaining GDD Heat margin Fit vs typical target
Apr 15 4513 +3513 Comfortable
May 1 4305 +3305 Comfortable
May 15 4077 +3077 Comfortable
Jun 1 3750 +2750 Comfortable
Jun 15 3451 +2451 Comfortable
Jul 1 3072 +2072 Comfortable

Best Cabbage Varieties for Seattle

The season in Seattle usually supports most cabbage varieties comfortably, which means the more useful decision is what kind of crop you want rather than simply how fast it finishes.

Varieties that often fit well here include:

Variety class Typical days to maturity Typical GDD need Local fit
Very early 60–70 800 Good fit
Early 70–80 900 Good fit
Mid-season 80–95 1000 Good fit
Late 95–110 1150 Good fit

Main risk: When this crop disappoints here, the problem is usually practical rather than climatic. Timing, steady growth, and harvest stage matter more than season length.

How Frost Affects Cabbage in Seattle

Seattle usually has about 249 frost-free days, with a typical last spring frost around March 13 and a typical first fall frost around November 17.

Typical last spring frost March 13
Typical first fall frost November 17
Typical frost-free days 249
Minimum safe temperature 28°F / -2 °C

Cabbage is generally somewhat frost tolerant and temperatures below about 28°F ( -2 °C) can slow growth or damage plants.

Cabbage is usually tolerant enough of cool conditions that light frost is not the main concern. The more useful question is how early planting affects establishment and overall crop quality.

When this crop disappoints in Seattle, the issue is usually management rather than climate fit. Timing, consistency, and harvest decisions matter more than season length.

In Seattle, the local season usually gives cabbage plenty of breathing room when planting happens around February 20. Local gardens do not all warm and cool at the same pace. For a better local margin, gardeners usually do best in south-facing walls, sheltered gardens, raised beds, and sunnier urban lots. Cooler spots like low spots, exposed sites, and shadier yards often make timing tighter. For cabbage, the best local sites often help the crop get moving earlier and make timing a little more forgiving.

Related crops

Related crops worth comparing for the same city:

For a broader local overview, see the Seattle planting guide. You can also use the Growing Degree Day Planner to test planting dates and crop timing.