Blog

When to Plant Yard Long Beans in Jefferson County, WA

Jefferson County, Washington Zone 8b May

Your May game plan for Jefferson County, Washington

We've pulled the most time-sensitive tasks for Jefferson County, Washington this May and put them front and centre. Tackle them in order.

Avg. last frost April 14
Avg. first frost October 29
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.9 hrs
June will be here before you know it — start on
  • Starting indoors: yard long beans
  • First harvests: yard long beans

Instant PDF download. No spam, unsubscribe any time.

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.

Jefferson County, Washington is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 29, giving you a growing season of approximately 198 days.

At an elevation of 205 feet, Jefferson County receives approximately 40.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Yard Long Beans during the growing season.

Jefferson County, WA (Zone 8b) Moderate season
198 days
Last Spring Frost April 14
198 growing days
First Fall Frost October 29

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (88 days to spare)
Start indoors: Feb 16 Transplant: Apr 20 🍅 Harvest: Jun 15 – Jul 27
Recommended (50%) ✓ Fits season (86 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 4
Safe Start (90%) ✓ Fits season (82 days to spare)
Start indoors: Mar 21 Transplant: May 23 🍅 Harvest: Jul 18 – Aug 29

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 Jefferson County

How your county's soil matches Yard Long Beans's growing requirements.

Soil pH

Your soil pH (5.7–6.8) overlaps with Yard Long Beans's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Jefferson County is excellent for Yard Long Beans — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Yard Long Beans.

Organic Matter

Organic matter is excellent (5.7%) — Yard Long Beans will thrive.

How to Plant Yard Long Beans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Yard Long Beans

4
successive plantings in your 198-day season

Sow every 6.3 weeks. Last sowing by Aug 10 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 769 gal / 100 sq ft

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 6.4" 0" ❄️ Dormant
Feb 4.7" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 4.3" 2.6" 1.7" 💧 Light watering
May 4.3" 2.1" 2.2" 🚿 Regular watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 0.5" 3.8" 🚿 Regular watering
Aug 4.3" 0.6" 3.7" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 6.3" 0" ❄️ Dormant
Dec 7.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jefferson 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 needs ~1,080 GDD — county provides 3,168 GDD Excellent fit

Yard Long Beans Planting Timeline — Jefferson County, WA

Yard Long Beans Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 21 Apr 21 – May 12
Harvest June 23 Jun 23 – Aug 4

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
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

55–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

198 days in Jefferson County

Growing Tips for Yard Long Beans in Jefferson County

Direct sow Yard Long Beans outdoors after April 14 in Jefferson 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

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yard Long Beans in Jefferson County, WA?

Jefferson County is in Zone 8b with an average last frost of April 14. Plan your Yard Long Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, WA?

Jefferson County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 29.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.