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When to Plant Winter Melon in King County, WA

Winter melon (wax gourd) is a large Asian squash with a waxy white coating that allows long storage. The mild flesh is used in soups and stir-fries.

King County, Washington is in USDA Zone 8b. The average last spring frost is April 7 and the first fall frost is October 30, giving you a growing season of approximately 206 days.

At an elevation of 258 feet, King County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Winter Melon during the growing season.

King County, WA (Zone 8b) Long season
206 days
Last Spring Frost April 7
206 growing days
First Fall Frost October 30

King County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Feb 3 Transplant: Apr 7 🍅 Harvest: Jul 7 – Aug 25
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jul 21 – Sep 8
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: Apr 1 Transplant: Jun 3 🍅 Harvest: Sep 2 – Oct 21

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 428 gal / 100 sq ft
Winter Melon needs ~1,759 GDD — county provides 3,450 GDD Excellent fit

Winter Melon Planting Timeline โ€” King County, WA

Winter Melon Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 โ€“ Mar 3
Transplant Outdoors April 21 Apr 21 โ€“ May 5
Direct Sow April 14 Apr 14 โ€“ May 5
Harvest July 21 Jul 21 โ€“ Sep 8

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8b

Growing Season

206 days

Growing Tips for King County

Start seeds indoors 3-4 weeks early. Provide ample space for sprawling vines. Harvest when the waxy coating develops on the rind. Fruits can weigh 15-30 pounds.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Winter Melon in King County, WA?

King County is in Zone 8b with an average last frost of April 7. Plan your Winter Melon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is King County, WA?

King County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 7 and first fall frost is October 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help King County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for King County, WA. Local conditions may vary. Last updated: April 2026.