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When to Plant Bitter Melon in Adams 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.

Adams County, Washington is in USDA Zone 6b. The average last spring frost is May 7 and the first fall frost is October 3, giving you a growing season of approximately 149 days.

At an elevation of 2,402 feet, Adams County receives approximately 17.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Bitter Melon during the growing season. With low rainfall, drip irrigation is essential for growing Bitter Melon successfully. Mulch heavily to conserve soil moisture.

Adams County, WA (Zone 6b) Short season
149 days
Last Spring Frost May 7
149 growing days
First Fall Frost October 3

Adams 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 (33 days to spare)
Start indoors: Mar 2 Transplant: May 11 🍅 Harvest: Jul 13 – Aug 24
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Mar 12 Transplant: May 21 🍅 Harvest: Jul 23 – Sep 3
Safe Start (90%) ✓ Fits season (37 days to spare)
Start indoors: Mar 27 Transplant: Jun 5 🍅 Harvest: Aug 7 – Sep 18

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
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 824 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Bitter Melon needs ~1,369 GDD — county provides 2,719 GDD Excellent fit

Bitter Melon Planting Timeline โ€” Adams County, WA

Bitter Melon Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 โ€“ Mar 26
Transplant Outdoors May 21 May 21 โ€“ Jun 4
Direct Sow May 14 May 14 โ€“ Jun 4
Harvest July 23 Jul 23 โ€“ Sep 3

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
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

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6b

Growing Season

149 days

Growing Tips for Adams 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 Adams County, WA?

Adams County is in Zone 6b with an average last frost of May 7. Plan your Bitter Melon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Adams County, WA?

Adams County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 7 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Adams County gardeners in Zone 6b 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 Adams County, WA. Local conditions may vary. Last updated: April 2026.