Washington planting calendar

When to plant cantaloupe in Washington — sow, transplant & harvest dates

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

Cantaloupe planting timetable for Washington

Stage	When in Washington	Anchor
Start seeds indoors	late March (March 25)	3 weeks before the last frost (mid-April (Puget Sound))
Transplant outside	late April (April 29)	14 days after the last frost (mid-April (Puget Sound))
First harvest (estimate)	mid-July (July 18)	~80 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 Washington's climate shifts the cantaloupe dates

Washington's last spring frost averages mid-April (Puget Sound) and first fall frost early November (Puget Sound), which sets the whole planting clock. Washington is split by the Cascades into a mild, wet, long-season west and a colder, drier east. The Puget Sound lowland is the mildest belt. Wait for warm soil — cantaloupe stall in cold ground even after the air warms, so don't rush them out.

Cantaloupe (muskmelon) is one of the most heat-demanding cucurbits — soil temperature must reach 21 °C (70 °F) and night air temperatures should stay consistently above 15 °C before transplanting. Short-season zones 3-5 should start indoors 2-3 weeks early and use black plastic mulch to boost soil heat. Fruits ripen only in warm, dry conditions; humid climates favor powdery mildew and fruit rot, so zones 8-10 with hot summers are ideal. Withhold irrigation in the final 1-2 weeks before harvest to concentrate sugars.

Frost-risk note

Don't plant before mid-April (Puget Sound) — even a light frost will kill seedlings overnight. In the Cascades and northeast highlands (zone 4a) the safe date runs a week or two later.

Regional variation within Washington

the Cascades and northeast highlands (zone 4a) runs roughly 1-2 weeks behind the state average; the Puget Sound lowland around Seattle (zone 9a) can plant 1-2 weeks earlier.

Seattle — USDA zone 9a
Spokane — USDA zone 7a
Tacoma — USDA zone 8b
Vancouver — USDA zone 8b
Yakima — USDA zone 7a

What else to plant in Washington 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: 24-32 °C (75-90 °F).
Spacing: 36-48 inches (90-120 cm) between plants.
Days to harvest: ~80 days from planting out.

Frequently asked questions

When is the best time to plant cantaloupe in Washington?

In Washington (mostly USDA zone 8a), sow cantaloupe indoors around late March, transplant outdoors late April (after the last frost, mid-April), and harvest from mid-July. Cantaloupe 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 Washington?

Most of Washington sits in USDA hardiness zone 8a, with the state spanning roughly 4a-9a from the Cascades and northeast highlands (zone 4a) to the Puget Sound lowland around Seattle (zone 9a). The last spring frost averages mid-April (Puget Sound) and the first fall frost early November (Puget Sound).

Can you grow cantaloupe in Washington?

Yes. Washington's dominant zone 8a supports cantaloupe — the key is timing. Cantaloupe 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 Washington?

the Cascades and northeast highlands (zone 4a) runs roughly 1-2 weeks behind the state average; the Puget Sound lowland around Seattle (zone 9a) can plant 1-2 weeks earlier.

What else can I plant in Washington 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.