Oregon planting calendar

When to plant zucchini in Oregon — sow, transplant & harvest dates

Oregon is mostly USDA zone 8b (range 4b-9b). Dates below are derived from zucchini's frost tolerance and Oregon's frost window — not generic national averages.

Zucchini planting timetable for Oregon

Stage	When in Oregon	Anchor
Start seeds indoors	late March (March 25)	3 weeks before the last frost (mid-April (Willamette Valley))
Transplant outside	late April (April 29)	14 days after the last frost (mid-April (Willamette Valley))
First harvest (estimate)	late June (June 23)	~55 days from transplant

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Oregon's climate shifts the zucchini dates

Oregon's last spring frost averages mid-April (Willamette Valley) and first fall frost early November (Willamette Valley), which sets the whole planting clock. Oregon is split by the Cascades: a mild, wet, long-season west and a cold, dry, short-season high desert east. Wait for warm soil — zucchini stall in cold ground even after the air warms, so don't rush them out.

Zucchini is the fastest-maturing summer squash — soil must reach 18 °C (65 °F) before sowing or transplanting, as cold soil causes slow, weak germination and root rot. One or two plants per family member is usually sufficient; succession-sowing every 3-4 weeks extends harvest but rarely necessary given prolific production. Harvest fruit at 15-20 cm (6-8 inches) every 2-3 days to maintain plant productivity; leaving fruits to overgrow reduces total yield.

Frost-risk note

Don't plant before mid-April (Willamette Valley) — even a light frost will kill seedlings overnight. In the high desert and Cascades east of the mountains (zone 4b) the safe date runs a week or two later.

Regional variation within Oregon

the high desert and Cascades east of the mountains (zone 4b) runs roughly 1-2 weeks behind the state average; the Willamette Valley and southwest interior (zone 9b) can plant 1-2 weeks earlier.

Portland — USDA zone 9a
Eugene — USDA zone 8b
Salem — USDA zone 8b
Bend — USDA zone 6b
Medford — USDA zone 8a

What else to plant in Oregon around then

Pair the post-frost slot with other warm-season crops — peppers, beans, squash, and cucumbers.

Quick-grow guide

Sun: Full sun — 6-8 hours direct.
Soil temperature for germination: 21-29 °C (70-85 °F).
Spacing: 24-36 inches (60-90 cm) between plants.
Days to harvest: ~55 days from planting out.

Frequently asked questions

When is the best time to plant zucchini in Oregon?

In Oregon (mostly USDA zone 8b), sow zucchini indoors around late March, transplant outdoors late April (after the last frost, mid-April), and harvest from late June. Zucchini are frost-tender — a single light frost kills seedlings, so they only go outside once frost danger has fully passed and the soil is warm.

What USDA zone is Oregon?

Most of Oregon sits in USDA hardiness zone 8b, with the state spanning roughly 4b-9b from the high desert and Cascades east of the mountains (zone 4b) to the Willamette Valley and southwest interior (zone 9b). The last spring frost averages mid-April (Willamette Valley) and the first fall frost early November (Willamette Valley).

Can you grow zucchini in Oregon?

Yes. Oregon's dominant zone 8b supports zucchini — the key is timing. Zucchini are frost-tender — a single light frost kills seedlings, so they only go outside once frost danger has fully passed and the soil is warm.

Does the planting date change across Oregon?

the high desert and Cascades east of the mountains (zone 4b) runs roughly 1-2 weeks behind the state average; the Willamette Valley and southwest interior (zone 9b) can plant 1-2 weeks earlier.

What else can I plant in Oregon around the same time?

Pair the post-frost slot with other warm-season crops — peppers, beans, squash, and cucumbers.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.