When to Plant Yard Long Beans in King County, WA
King County, Washington gardeners: here's your May plan
Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.
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Start yard long beans indoors
Your window is short. These crops want several weeks of indoor growth before they go outside.
A few tasks this May that'll pay off in June
- First harvests: yard long beans
Yard long beans are a tropical legume that produces slender pods up to 24 inches long. They are a staple in Southeast Asian cooking and thrive in hot weather.
King County, Washington is in USDA Zone 9a. 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 89°F, providing good warmth for Yard Long Beans during the growing season.
King County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.4
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 King County
How your county's soil matches Yard Long Beans's growing requirements.
Soil pH
Your soil pH (5.7–6.4) overlaps with Yard Long Beans's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in King County is excellent for Yard Long Beans — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.5%) — Yard Long Beans will thrive.
How to Plant Yard Long Beans
Succession Planting Yard Long Beans
Sow every 6.3 weeks. Last sowing by Aug 11 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Yard Long Beans
Yard Long Beans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Yard Long Beans Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.9" | 0" | ❄️ Dormant |
| Feb | — | 4.5" | 0" | ❄️ Dormant |
| Mar | — | 3.4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| May | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Jun | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Jul | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Aug | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Nov | — | 5.6" | 0" | ❄️ Dormant |
| Dec | — | 5.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in King County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Yard Long Beans 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.
Yard Long Beans Planting Timeline — King County, WA
Yard Long Beans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 24 | Feb 24 – Mar 10 |
| Transplant Outdoors | April 14 | Apr 14 – Apr 28 |
| Direct Sow | April 7 | Apr 7 – Apr 28 |
| Harvest | June 9 | Jun 9 – Jul 21 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
55–80 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
206 days in King County
Growing Tips for Yard Long Beans in King County
Direct sow Yard Long Beans outdoors after April 07 in King County when soil has warmed and frost danger has passed.
Common pests for Yard Long Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow after soil is warm. Provide tall poles or trellising as vines can reach 8-10 feet. Harvest when pods are pencil-thick before seeds bulge. Cook quickly for best texture.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Yard Long Beans in Other Locations
Frequently Asked Questions
When should I plant Yard Long Beans in King County, WA?
King County is in Zone 9a with an average last frost of April 7. Plan your Yard Long Beans planting based on this frost date — see the calendar above for exact timing.
What planting zone is King County, WA?
King County, Washington is in USDA Hardiness Zone 9a. The average last spring frost is April 7 and first fall frost is October 30.
Your King County Garden Planner — Free
A 24-page printable planner built for King County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.