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When to Plant Bitter Melon in Clackamas County, OR

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.

Clackamas County, Oregon is in USDA Zone 8a. The average last spring frost is April 14 and the first fall frost is October 28, giving you a growing season of approximately 197 days.

At an elevation of 199 feet, Clackamas County receives approximately 53.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Bitter Melon during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Bitter Melon root diseases.

Clackamas County, OR (Zone 8a) Moderate season
197 days
Last Spring Frost April 14
197 growing days
First Fall Frost October 28

Clackamas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Start indoors: Feb 14 Transplant: Apr 18 🍅 Harvest: Jun 20 – Aug 1
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 30 – Aug 11
Safe Start (90%) ✓ Fits season (82 days to spare)
Start indoors: Mar 19 Transplant: May 21 🍅 Harvest: Jul 23 – Sep 3

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.

Soil Compatibility in Clackamas County

How your county's soil matches Bitter Melon's growing requirements.

Soil pH

Your soil pH (5.7โ€“6.3) overlaps with Bitter Melon's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Clackamas County is excellent for Bitter Melon โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.7%) โ€” Bitter Melon will thrive.

How to Plant Bitter Melon

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Bitter Melon

3
successive plantings in your 197-day season

Sow every 6.9 weeks. Last sowing by Jul 30 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Bitter Melon

Bitter Melon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Bitter Melon Needs Rainfall You Supplement Action
Jan โ€” 8.3" 0" โ„๏ธ Dormant
Feb โ€” 5.3" 0" โ„๏ธ Dormant
Mar โ€” 4.8" 0" โ„๏ธ Dormant
Apr 4.3" 4" 0.3" ๐Ÿ’ง Light watering
May 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Jun 4.3" 2.1" 2.2" ๐Ÿšฟ Regular watering
Jul 4.3" 0.8" 3.5" ๐Ÿšฟ Regular watering
Aug 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Sep 4.3" 2.2" 2.1" ๐Ÿ’ง Light watering
Oct 4.3" 4.7" 0" โœ… Rainfall sufficient
Nov โ€” 8.2" 0" โ„๏ธ Dormant
Dec โ€” 8.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Clackamas County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Bitter Melon Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Bitter Melon needs ~1,031 GDD — county provides 2,708 GDD Excellent fit

Bitter Melon Planting Timeline โ€” Clackamas County, OR

Bitter Melon Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 โ€“ Mar 10
Transplant Outdoors April 28 Apr 28 โ€“ May 12
Direct Sow April 21 Apr 21 โ€“ May 12
Harvest June 30 Jun 30 โ€“ Aug 11

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 Harvest
July Harvest
August Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

197 days in Clackamas County

Growing Tips for Bitter Melon in Clackamas County

Direct sow Bitter Melon outdoors after April 14 in Clackamas County when soil has warmed and frost danger has passed.

Common pests for Bitter Melon in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Bitter Melon in Clackamas County, OR?

Clackamas County is in Zone 8a with an average last frost of April 14. Plan your Bitter Melon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clackamas County, OR?

Clackamas County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is April 14 and first fall frost is October 28.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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