Bellevue, WA Planting Dates — Moon Phase Garden

The four dates that matter

Date	When	What it means
Last spring frost (50%)	Mar 20	Half of all years see a freeze after this date. It is an average, not a guarantee.
Last spring frost (10%)	Apr 10	Only one year in ten freezes after this. Use it for anything you cannot afford to replant.
First fall frost (50%)	Nov 13	Half of all years freeze before this date. Fall crops are counted back from here.
First fall frost (10%)	Oct 26	An early-freeze year. If a crop must finish, aim to harvest before this.

USDA zone 9a 238 frost-free days Modelled estimate

Spring & summer planting in Bellevue

Dates are calculated from this location's own last-frost date, not from a generic zone chart. “Best moon days” are the days inside each window that fall in the crop's traditional phase — the same rule the app uses.

Crop	Start seed indoors	Plant outdoors	Best moon days	Days to harvest
Strawberry (crowns) transplant	—	Jan 19 – Feb 27	Feb 1 Full Moon	perennial — first real harvest next season
Garlic cloves/sets Better planted in fall — see below	—	Feb 1 – Mar 4	Feb 2–7 Waning Gibbous	240–300
Asparagus (crowns) transplant	—	Feb 6 – Mar 13	Feb 24 First Quarter	perennial — first real harvest 2–3 years
Chives either	Jan 23	Feb 6 – Mar 13	Feb 18–23 Waxing Crescent	75–90
Onion (from sets/transplants) cloves/sets	—	Feb 6 – Mar 13	Feb 6–8, Mar 4–6 Waning Gibbous	90–120
Peas (English/snap) direct sow	—	Feb 6 – Mar 13	Feb 24 First Quarter	55–75
Spinach direct sow	—	Feb 6 – Mar 13	Feb 18–23 Waxing Crescent	35–50
Cabbage transplant	Jan 16	Feb 13 – Mar 13	Feb 18–23 Waxing Crescent	65–90
Collards either	Feb 6	Feb 13 – Apr 3	Feb 18–23 Waxing Crescent	55–85
Kale either	Feb 6	Feb 13 – Mar 20	Feb 18–23 Waxing Crescent	50–65
Lettuce (leaf) either	Feb 13	Feb 13 – Apr 10	Feb 18–23 Waxing Crescent	40–55
Potato cloves/sets	—	Feb 13 – Mar 20	Mar 3 Full Moon	70–120
Radish direct sow	—	Feb 13 – Apr 10	Mar 4–9 Waning Gibbous	22–35
Turnip direct sow	—	Feb 13 – Mar 27	Mar 4–9 Waning Gibbous	40–60
Broccoli transplant	Jan 16	Feb 18 – Mar 20	Feb 18–23 Waxing Crescent	55–80
Brussels Sprouts transplant	Jan 16	Feb 18 – Mar 20	Feb 18–23 Waxing Crescent	90–110
Leek transplant	Jan 9	Feb 18 – Mar 20	Mar 4–9 Waning Gibbous	100–120
Lettuce (head) transplant	Jan 30	Feb 18 – Mar 20	Feb 18–23 Waxing Crescent	60–85
Parsley either	Jan 16	Feb 18 – Mar 27	Feb 18–23 Waxing Crescent	70–90
Parsnip direct sow	—	Feb 18 – Mar 27	Mar 3 Full Moon	100–150
Shallot cloves/sets Better planted in fall — see below	—	Feb 18 – Mar 20	Mar 4–9 Waning Gibbous	90–120
Beet direct sow	—	Feb 20 – Apr 10	Mar 3, Apr 1 Full Moon	50–65
Kohlrabi either	Feb 6	Feb 20 – Mar 27	Feb 20–23, Mar 19–20 Waxing Crescent	45–60
Carrot direct sow	—	Feb 27 – Apr 10	Mar 3, Apr 1 Full Moon	65–85
Cauliflower transplant	Jan 16	Feb 27 – Mar 20	Mar 19–20 Waxing Crescent	55–80
Cilantro direct sow	—	Feb 27 – Apr 10	Mar 19–24 Waxing Crescent	45–70
Swiss Chard direct sow	—	Feb 27 – Apr 19	Mar 19–24 Waxing Crescent	50–60
Dill direct sow	—	Mar 6 – Apr 19	Mar 19–24 Waxing Crescent	40–60
Cucumber either	Feb 27	Mar 20 – Apr 19	Mar 25 First Quarter	50–70
Green Beans (bush) direct sow	—	Mar 20 – May 4	Mar 25, Apr 23 First Quarter	50–65
Oregano transplant	Jan 23	Mar 20 – Apr 10	Mar 25 First Quarter	cut as needed
Sage transplant	Jan 23	Mar 20 – Apr 10	Mar 25 First Quarter	cut as needed
Sweet Corn direct sow	—	Mar 20 – May 4	Mar 25, Apr 23 First Quarter	60–100
Thyme transplant	Jan 23	Mar 20 – Apr 10	Mar 25 First Quarter	cut as needed
Zucchini / Summer Squash either	Feb 27	Mar 20 – Apr 19	Mar 25 First Quarter	45–60
Basil either	Feb 6	Mar 27 – Apr 19	Apr 18–19 Waxing Crescent	30–60
Dry Beans direct sow	—	Mar 27 – Apr 24	Apr 23 First Quarter	85–100
Pole Beans direct sow	—	Mar 27 – Apr 29	Apr 23 First Quarter	60–75
Pumpkin direct sow	Feb 27	Mar 27 – Apr 24	Apr 23 First Quarter	90–120
Rosemary transplant	Mar 20	Mar 27 – Apr 19	— First Quarter	cut as needed
Tomatillo transplant	Feb 6	Mar 27 – Apr 19	— First Quarter	60–75
Tomato transplant	Feb 6	Mar 27 – Apr 19	— First Quarter	60–85
Winter Squash direct sow	Feb 27	Mar 27 – Apr 24	Apr 23 First Quarter	85–110
Cantaloupe / Muskmelon either	Feb 27	Apr 3 – Apr 24	Apr 23 First Quarter	75–90
Eggplant transplant	Jan 23	Apr 3 – Apr 24	Apr 23 First Quarter	60–90
Okra direct sow	Feb 20	Apr 3 – Apr 29	Apr 23 First Quarter	50–70
Pepper transplant	Jan 23	Apr 3 – Apr 24	Apr 23 First Quarter	60–90
Sweet Potato slips	—	Apr 3 – Apr 29	Apr 3–8 Waning Gibbous	90–150
Watermelon either	Feb 27	Apr 3 – Apr 24	Apr 23 First Quarter	70–90

Fall planting in Bellevue

Fall dates count backward from the first frost, and they add time back for the “fall factor” — days are shortening and cooling, so a crop grows slower than the seed packet promises. Sowing late is the single most common way a fall garden fails.

Crop	Sow or set out	Best moon days	Days to harvest	Hardiness
Tomato	Jun 28 – Aug 3	Jul 21	60–85	very tender
Brussels Sprouts	Jul 1 – Jul 18	Jul 15–18	90–110	hardy
Potato	Jul 6 – Aug 7	Jul 29	70–120	semi-hardy
Sweet Corn	Jul 11 – Aug 3	Jul 21	60–100	tender
Pole Beans	Jul 21 – Aug 3	Jul 21	60–75	tender
Parsley	Jul 24 – Aug 7	—	70–90	semi-hardy
Okra	Jul 26 – Aug 25	Aug 19	50–70	very tender
Cabbage	Jul 31 – Aug 12	—	65–90	hardy
Carrot	Jul 31 – Aug 12	—	65–85	semi-hardy
Collards	Jul 31 – Aug 22	Aug 13–18	55–85	hardy
Cucumber	Jul 31 – Aug 13	—	50–70	tender
Broccoli	Aug 5 – Aug 22	Aug 13–18	55–80	hardy
Cauliflower	Aug 5 – Aug 22	Aug 13–18	55–80	semi-hardy
Green Beans (bush)	Aug 5 – Aug 13	—	50–65	tender
Lettuce (head)	Aug 5 – Aug 17	Aug 13–17	60–85	semi-hardy
Peas (English/snap)	Aug 5 – Aug 22	Aug 19	55–75	hardy
Beet	Aug 10 – Aug 27	Aug 27	50–65	semi-hardy
Kale	Aug 10 – Aug 27	Aug 13–18	50–65	hardy
Swiss Chard	Aug 10 – Aug 27	Aug 13–18	50–60	semi-hardy
Zucchini / Summer Squash	Aug 10 – Aug 18	—	45–60	tender
Basil	Aug 15 – Sep 2	Aug 15–18	30–60	very tender
Kohlrabi	Aug 15 – Sep 1	Aug 15–18	45–60	hardy
Cilantro	Aug 20 – Sep 1	—	45–70	semi-hardy
Lettuce (leaf)	Aug 20 – Sep 6	—	40–55	semi-hardy
Turnip	Aug 20 – Sep 6	Aug 28–Sep 2	40–60	hardy
Spinach	Aug 25 – Sep 11	Sep 11	35–50	hardy
Dill	Aug 30 – Sep 6	—	40–60	semi-hardy
Radish	Aug 30 – Sep 24	Aug 30–Sep 3	22–35	hardy
Garlic	Oct 14 – Dec 4	Oct 26–31	240–300	hardy
Shallot	Oct 28 – Nov 28	Oct 28–31, Nov 25–26	90–120	hardy

Bottom line: the 50% frost date is a coin flip, not a green light. If you would be sick about losing a flat of tomatoes, plant to the Apr 10 date instead and keep a row cover handy either way.

Where these numbers come from

There is no long-record weather station inside Bellevue itself, so these frost dates are modelled, not observed. They come from a half-degree climate grid built by fitting the freeze dates of 6,808 NOAA stations (1991–2020 Normals) against terrain and the USDA 2023 hardiness raster, then reading the cell your city sits in. Checked against the stations themselves, that model lands within about a week on average — and its zone matches the station's exactly 67% of the time and within one half-zone 97% of the time. A cell covers roughly 35 by 28 miles, so this is a neighborhood answer, not a backyard one. If there is a station-backed location near you, prefer it.

How precise is any of this?

Extension recommendations for the same crop routinely disagree by two to four weeks, and occasionally more, so these offsets should be presented as windows and starting points rather than deadlines. Three things drive the spread. (1) Regional risk tolerance: for warm-season crops, Colorado State and Utah State put tomatoes, peppers and melons out about 14 days after the last frost, while University of Missouri's calendar works out to roughly 25-35 days after the last frost and University of Maryland's window runs from the frost date itself out to 45 days past it. That is a real 6-week spread for the single most popular garden crop, and it exists because a short-season mountain state is optimizing against a short season while a humid continental state is optimizing against cold, wet spring soil. (2) Soil temperature versus calendar date: most Extension services now say the honest trigger is soil temperature at 4 inches, not the frost date, and the frost-relative number is a convenience translation. A cold, wet spring can push the real date two or three weeks past the calendar recommendation. (3) Days-to-maturity is variety-specific and is measured differently for direct-seeded versus transplanted crops - seed catalogs count from transplant date for tomatoes, peppers, eggplant and cole crops, but from sowing for roots and greens - so a 'days to maturity' range of 60-85 for tomato is genuinely 60-85 depending on which packet you bought. Additionally, the average last frost is a 50% probability, meaning half of all years have a frost after that date; Extension services commonly advise waiting 1-2 weeks past it for anything frost-tender, or being prepared to cover. Treat every number here as plus or minus about 10-14 days.

On the station itself: a weather station is one point. Cities hold their heat, valleys pool cold air, and a garden on a north slope can run two weeks behind one a mile away. Treat this page as your starting point and let your own garden correct it — that is exactly what the journal in the app is for.

Nearby locations

Kirkland, WA zone 9a Renton, WA zone 8b Seattle, WA zone 9a Kent, WA zone 8b Federal Way, WA zone 8b Everett, WA zone 9a

Want this on your phone, in your garden? Moon Phase Garden keeps your frost dates, your planting windows and tonight's moon phase in one place, works offline, and lets you override these dates with what your own garden actually does. Free and ad-free.

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