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When to Plant Bitter Melon in Island County, WA

Bitter melon is a tropical vine producing warty, bitter fruits used in Asian and Indian cuisine. The intense bitterness is prized for its culinary and health properties.

Island County, Washington is in USDA Zone 8a. The average last spring frost is March 30 and the first fall frost is November 3, giving you a growing season of approximately 218 days.

At an elevation of 9 feet, Island County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Bitter Melon during the growing season.

Island County, WA (Zone 8a) Long season
218 days
Last Spring Frost March 30
218 growing days
First Fall Frost November 3

Island County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (102 days to spare)
Start indoors: Feb 1 Transplant: Apr 5 🍅 Harvest: Jun 7 – Jul 19
Recommended (50%) ✓ Fits season (99 days to spare)
Start indoors: Feb 9 Transplant: Apr 13 🍅 Harvest: Jun 15 – Jul 27
Safe Start (90%) ✓ Fits season (89 days to spare)
Start indoors: Mar 12 Transplant: May 14 🍅 Harvest: Jul 16 – Aug 27

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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 239 gal / 100 sq ft
Bitter Melon needs ~1,031 GDD — county provides 2,997 GDD Excellent fit

Bitter Melon Planting Timeline โ€” Island County, WA

Bitter Melon Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 โ€“ Feb 23
Transplant Outdoors April 13 Apr 13 โ€“ Apr 27
Direct Sow April 6 Apr 6 โ€“ Apr 27
Harvest June 15 Jun 15 โ€“ Jul 27

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8a

Growing Season

218 days

Growing Tips for Island County

Start seeds indoors 4 weeks before last frost. Provide a trellis for climbing. Harvest fruits while still green and firm. Reduce bitterness by salting sliced fruit before cooking.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Bitter Melon in Island County, WA?

Island County is in Zone 8a with an average last frost of March 30. Plan your Bitter Melon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Island County, WA?

Island County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is March 30 and first fall frost is November 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Island County gardeners in Zone 8a 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 Island County, WA. Local conditions may vary. Last updated: April 2026.