Gardening in Seattle-Tacoma-Bellevue, WA
This metro spans USDA zones 7a to 9a, so there is no single zone for Seattle-Tacoma-Bellevue, WA and anyone who gives you one is rounding. 57% of its ZIP codes are zone 8b; the rest are not.
Which zone you are in depends where you are
Seattle-Tacoma-Bellevue, WA covers 4 hardiness zones. A guide that gives the metro one zone has picked whichever is largest and rounded everyone else into it — which is fine for the 57% in zone 8b and wrong for the other 43%. Here is the actual split.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 8b | 95 | 57% | |
| 9a | 62 | 37% | |
| 8a | 9 | 5% | |
| 7a | 1 | 1% |
Zones are published per ZIP code, so yours is exact even though the metro's is not. The hardiness tool will tell you which one you are in.
Your freeze dates
Those are the earliest and latest medians among the 23 stations serving this metro — not an average, and not one station standing in for the rest. Half of years freeze later than a station's own median.
The spread is the point. Even in a metro that is one hardiness zone throughout, its stations disagree about the last spring freeze. Hardiness zone and frost date measure different things — a zone is the average annual coldest night, a freeze date is when the season turns — and a place can be uniform in one and varied in the other. Use the tools below with your own ZIP rather than the ends of this range.
Your growing season
NOAA publishes a growing-season length for each station, and across the 23 stations serving Seattle-Tacoma-Bellevue, WA it runs 114–266 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 68–76 °F , below the 90 °F point where cool-season crops reliably bolt.
When to start seeds in Seattle-Tacoma-Bellevue, WA
Every spring job for 63 crop dates, counted from this metro's own last spring freeze. Each is a range across all 23 stations — the earliest and latest that job falls anywhere in the metro — because no one station speaks for the whole area.
| Crop | Job | When | Offset |
|---|---|---|---|
| Green Onions | Start indoors | January 5 – March 30 | 8 weeks before |
| Peppers | Start indoors | January 5 – March 30 | 8 weeks before |
| Broccoli | Start indoors | January 19 – April 13 | 6 weeks before |
| Cabbage | Start indoors | January 19 – April 13 | 6 weeks before |
| Collards | Start indoors | January 19 – April 13 | 6 weeks before |
| Kale | Start indoors | January 19 – April 13 | 6 weeks before |
| Leaf Lettuce | Start indoors | January 19 – April 13 | 6 weeks before |
| Peas | Direct sow | January 19 – April 13 | 6 weeks before |
| Spinach | Direct sow | January 19 – April 13 | 6 weeks before |
| Sweet Potato | Start indoors | January 19 – April 13 | 6 weeks before |
| Tomatoes | Start indoors | January 19 – April 13 | 6 weeks before |
| Bok Choy | Start indoors | January 26 – April 20 | 5 weeks before |
| Kohlrabi | Start indoors | January 26 – April 20 | 5 weeks before |
| Swiss Chard | Start indoors | January 26 – April 20 | 5 weeks before |
| Arugula | Direct sow | February 2 – April 27 | 4 weeks before |
| Baby Salad Greens | Direct sow | February 2 – April 27 | 4 weeks before |
| Beets | Direct sow | February 2 – April 27 | 4 weeks before |
| Green Onions | Direct sow | February 2 – April 27 | 4 weeks before |
| Mustard Greens | Direct sow | February 2 – April 27 | 4 weeks before |
| Okra | Start indoors | February 2 – April 27 | 4 weeks before |
| Radishes | Direct sow | February 2 – April 27 | 4 weeks before |
| Turnips | Direct sow | February 2 – April 27 | 4 weeks before |
| Cabbage | Set out | February 9 – May 4 | 3 weeks before |
| Carrots | Direct sow | February 9 – May 4 | 3 weeks before |
| Collards | Direct sow | February 9 – May 4 | 3 weeks before |
| Collards | Set out | February 9 – May 4 | 3 weeks before |
| Cucumbers | Start indoors | February 9 – May 4 | 3 weeks before |
| Green Onions | Set out | February 9 – May 4 | 3 weeks before |
| Kale | Direct sow | February 9 – May 4 | 3 weeks before |
| Kale | Set out | February 9 – May 4 | 3 weeks before |
| Kohlrabi | Direct sow | February 9 – May 4 | 3 weeks before |
| Kohlrabi | Set out | February 9 – May 4 | 3 weeks before |
| Leaf Lettuce | Direct sow | February 9 – May 4 | 3 weeks before |
| Pumpkins | Start indoors | February 9 – May 4 | 3 weeks before |
| Summer Squash | Start indoors | February 9 – May 4 | 3 weeks before |
| Winter Squash | Start indoors | February 9 – May 4 | 3 weeks before |
| Zucchini | Start indoors | February 9 – May 4 | 3 weeks before |
| Bok Choy | Direct sow | February 16 – May 11 | 2 weeks before |
| Bok Choy | Set out | February 16 – May 11 | 2 weeks before |
| Broccoli | Set out | February 16 – May 11 | 2 weeks before |
| Cilantro | Direct sow | February 16 – May 11 | 2 weeks before |
| Leaf Lettuce | Set out | February 16 – May 11 | 2 weeks before |
| Swiss Chard | Direct sow | February 16 – May 11 | 2 weeks before |
| Swiss Chard | Set out | February 16 – May 11 | 2 weeks before |
| Dill | Direct sow | February 23 – May 18 | 1 week before |
| Bush Beans | Direct sow | March 9 – June 1 | 1 week after |
| Cucumbers | Set out | March 9 – June 1 | 1 week after |
| Pumpkins | Direct sow | March 9 – June 1 | 1 week after |
| Pumpkins | Set out | March 9 – June 1 | 1 week after |
| Summer Squash | Direct sow | March 9 – June 1 | 1 week after |
| Summer Squash | Set out | March 9 – June 1 | 1 week after |
| Sweet Corn | Direct sow | March 9 – June 1 | 1 week after |
| Tomatoes | Set out | March 9 – June 1 | 1 week after |
| Winter Squash | Direct sow | March 9 – June 1 | 1 week after |
| Winter Squash | Set out | March 9 – June 1 | 1 week after |
| Zucchini | Direct sow | March 9 – June 1 | 1 week after |
| Zucchini | Set out | March 9 – June 1 | 1 week after |
| Cucumbers | Direct sow | March 16 – June 8 | 2 weeks after |
| Okra | Direct sow | March 16 – June 8 | 2 weeks after |
| Okra | Set out | March 16 – June 8 | 2 weeks after |
| Peppers | Set out | March 16 – June 8 | 2 weeks after |
| Southern Peas | Direct sow | March 16 – June 8 | 2 weeks after |
| Sweet Potato | Set out | March 16 – June 8 | 2 weeks after |
The week offsets are conventional extension guidance and vary by variety; the freeze dates they are counted from are measured. For a single date rather than a range, run when do I start my seeds? with your own ZIP code.
What survives the winter changes across Seattle-Tacoma-Bellevue, WA
Of 74 perennial fruits, nuts, berries, vegetables and herbs, 58 come through the winter in zone 7a and only 46 in zone 9a. That is a different garden at each end of the same metro.
| Zone | ZIPs | Survive | Fail for being too warm |
|---|---|---|---|
| 7a | 1 | 58 of 74 | 1 |
| 8a | 9 | 57 of 74 | 8 |
| 8b | 95 | 54 of 74 | 11 |
| 9a | 62 | 46 of 74 | 25 |
The last column is the counterintuitive one, and it is why the totals do not simply rise as the winters get milder. Most temperate fruit needs a documented number of hours below about 45 °F to break dormancy and set a crop, so an apple fails in a winter that is too warm; currants and rhubarb cook in the summer heat that comes with it. See the full list with reasons.
The 23 stations behind these numbers
Every figure above comes from these, and each is named so you can check it. Distances vary by ZIP code, so the tools report yours rather than this page guessing.
| Station | NOAA ID | Last spring freeze | First fall freeze | Season |
|---|---|---|---|---|
| Arlington, WA | USC00450257 | April 22 | October 19 | 181 days |
| Baring, WA | USC00450456 | April 14 | October 29 | 197 days |
| Buckley 1 NE, WA | USC00450945 | April 7 | October 30 | 204 days |
| Cedar Lake, WA | USC00451233 | April 23 | November 1 | 193 days |
| Everett Snohomish AP, WA | USW00024222 | March 9 | November 17 | 250 days |
| Everett, WA | USC00452675 | March 24 | November 2 | 223 days |
| Holden Village, WA | USC00453730 | May 25 | September 19 | 114 days |
| Kent, WA | USC00454169 | March 20 | November 10 | 233 days |
| Landsburg, WA | USC00454486 | April 20 | October 25 | 187 days |
| Longmire Rainier Nps, WA | USC00454764 | May 22 | October 3 | 134 days |
| Mcmillin Rsvr, WA | USC00455224 | April 11 | October 30 | 202 days |
| Monroe, WA | USC00455525 | April 17 | October 23 | 188 days |
| Mud Mtn Dam, WA | USC00455704 | April 18 | October 31 | 196 days |
| Palmer 3 Ese, WA | USC00456295 | April 3 | November 11 | 219 days |
| Renton Muni AP, WA | USW00094248 | March 13 | November 16 | 248 days |
| Seattle Boeing FLD, WA | USW00024234 | March 13 | November 17 | 247 days |
| Seattle Sand Pt Wsfo, WA | USW00094290 | March 8 | November 23 | 259 days |
| Seattle Tacoma INTL AP, WA | USW00024233 | March 2 | November 23 | 266 days |
| Snoqualmie Falls, WA | USC00457773 | March 30 | November 7 | 223 days |
| Startup 1 E, WA | USC00458034 | April 15 | October 25 | 192 days |
| Tacoma #1, WA | USC00458278 | March 8 | November 14 | 250 days |
| Tacoma Narrows AP, WA | USW00094274 | March 11 | November 21 | 254 days |
| Tolt S Fk Rsvr, WA | USC00458508 | April 13 | November 10 | 210 days |
These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.
Work out your own dates
Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.
- What survives my winter?
Runs on the hardiness zone, so it answers for all of Seattle-Tacoma-Bellevue, WA at once — zone across 74 perennial fruits, berries, vegetables and herbs.
- When do I start my seeds?
Dates every spring job from your own last freeze — sow indoors, set out, direct sow.
- When do I sow the next round?
How often each crop is worth re-sowing, and when the next sowing is due.
- What can I still plant?
Counts the growing days left before your first fall freeze, crop by crop.
Where these numbers come from
The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates are NOAA's 1991–2020 Climate Normals, read from every station whose normals cover a ZIP code in this metro. Nothing here is estimated, and no station stands in for another.
This page names no single station on purpose. Picking one to represent a metro sounds reasonable and is not: the station serving the most ZIP codes is an artifact of where ZIP centroids happen to fall, and it selects a lock on the Monongahela for Pittsburgh and a far southern suburb for Chicago. A range across every station is true; a single cited date for a whole metro is not.