When to Plant Bitter Melon in Walla Walla County, WA
Walla Walla County, Washington gardeners: here's your May plan
Your Walla Walla County, Washington garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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Set out bitter melon seedlings
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
June prep starts now
- Starting indoors: bitter melon
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.
Walla Walla County, Washington is in USDA Zone 7a. The average last spring frost is April 20 and the first fall frost is October 15, giving you a growing season of approximately 178 days.
At an elevation of 3,151 feet, Walla Walla County receives approximately 23.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Bitter Melon during the growing season.
Walla Walla County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
Drainage
Well Drained
Plant Planting Risk Windows
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 Walla Walla County
How your county's soil matches Bitter Melon's growing requirements.
Soil pH
Your soil pH (5.2–6.4) is more acidic than Bitter Melon prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Walla Walla County is excellent for Bitter Melon — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Bitter Melon will thrive.
How to Plant Bitter Melon
Succession Planting Bitter Melon
Sow every 6.9 weeks. Last sowing by Jul 17 to harvest before frost.
Plant Water Budget
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 | — | 2.9" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| May | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Jun | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Jul | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Aug | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Sep | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Oct | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Nov | — | 3.7" | 0" | ❄️ Dormant |
| Dec | — | 3.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Walla Walla County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 Planting Timeline — Walla Walla County, WA
Bitter Melon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 2 | Mar 2 – Mar 16 |
| Transplant Outdoors | May 4 | May 4 – May 18 |
| Direct Sow | April 27 | Apr 27 – May 18 |
| Harvest | July 6 | Jul 6 – Aug 17 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 7a
📆 Growing Season
178 days in Walla Walla County
Growing Tips for Bitter Melon in Walla Walla County
Direct sow Bitter Melon outdoors after April 20 in Walla Walla 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.
Walla Walla County receives only 24" of rain annually. Bitter Melon needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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
Check more plant combinations with our Companion Planting Checker →
Bitter Melon in Other Locations
Frequently Asked Questions
When should I plant Bitter Melon in Walla Walla County, WA?
Walla Walla County is in Zone 7a with an average last frost of April 20. Plan your Bitter Melon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Walla Walla County, WA?
Walla Walla County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 20 and first fall frost is October 15.
Your Walla Walla County Garden Planner — Free
A 24-page printable planner built for Walla Walla County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.