Alaska planting calendar

When to plant summer squash in Alaska — sow, transplant & harvest dates

Alaska is mostly USDA zone 4b (range 1a-8b). Dates below are derived from summer squash's frost tolerance and Alaska's frost window — not generic national averages.

Summer squash planting timetable for Alaska

Stage	When in Alaska	Anchor
Start seeds indoors	early May (May 4)	3 weeks before the last frost (late May)
Transplant outside	early June (June 8)	14 days after the last frost (late May)
First harvest (estimate)	early August (August 2)	~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 Alaska's climate shifts the summer squash dates

Alaska's last spring frost averages late May and first fall frost mid-September, which sets the whole planting clock. Alaska spans the widest zone range of any state, from sub-arctic interior to mild maritime southeast. Season length and summer light, not just cold, shape what grows. Wait for warm soil — summer squash stall in cold ground even after the air warms, so don't rush them out.

Summer squash (zucchini, yellow crookneck, pattypan) wants the same warm soil as cucumbers — 18 °C minimum at sowing depth. A single plant can outproduce a small family once it gets going, so don't over-plant.

Frost-risk note

Don't plant before late May — even a light frost will kill seedlings overnight. In the interior near Fairbanks (zone 1a-2b) the safe date runs a week or two later.

Regional variation within Alaska

the interior near Fairbanks (zone 1a-2b) runs roughly 1-2 weeks behind the state average; the southeast coast and panhandle around Sitka (zone 8b) can plant 1-2 weeks earlier.

Anchorage — USDA zone 5a
Fairbanks — USDA zone 2a
Juneau — USDA zone 7a
Sitka — USDA zone 8a

What else to plant in Alaska 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 summer squash in Alaska?

In Alaska (mostly USDA zone 4b), sow summer squash indoors around early May, transplant outdoors early June (after the last frost, late May), and harvest from early August. Summer squash 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 Alaska?

Most of Alaska sits in USDA hardiness zone 4b, with the state spanning roughly 1a-8b from the interior near Fairbanks (zone 1a-2b) to the southeast coast and panhandle around Sitka (zone 8b). The last spring frost averages late May and the first fall frost mid-September.

Can you grow summer squash in Alaska?

Yes. Alaska's dominant zone 4b supports summer squash — the key is timing. Summer squash 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 Alaska?

the interior near Fairbanks (zone 1a-2b) runs roughly 1-2 weeks behind the state average; the southeast coast and panhandle around Sitka (zone 8b) can plant 1-2 weeks earlier.

What else can I plant in Alaska 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.