When to plant zucchini in Washington
Washington spans USDA hardiness zones 4a-9a. Average last spring frost: 04-15 (W) to 05-25 (E). This calendar gives you the indoor start, transplant, and direct-sow dates for Cucurbita pepo.
Washington planting dates for zucchini
Dates for Washington vary significantly by region. Use the average frost date lookup for your specific ZIP code, then apply the standard offsets: start zucchini indoors 3 weeks before your last frost; transplant 1 weeks after last frost; direct sow 1 weeks after last frost.
Why these dates
Zucchini germinates fast in warm soil. Squash vine borer is the main killer in the eastern US - row covers until flowering, then hand-pick adults in late June.
The dates above are anchored to Washington's average last spring frost date of 04-15 (W) to 05-25 (E), with offsets standard across university Extension publications. For zone-specific local timing, use the frost date lookup tool with your ZIP code.
More on growing zucchini
The full growing guide for zucchini - varieties, soil, fertilization, pests, harvest, storage - is here: Zucchini growing guide.
More Washington planting information
- Full Washington planting calendar (all crops + ornamentals)
- Find your exact USDA zone by ZIP
- Look up your average frost dates
- Seed starting timeline calculator