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When to Plant Lima Beans in Jefferson County, WA

Jefferson County, Washington Zone 8b May

Your May gardening checklist

Your garden in Jefferson County, Washington is working on a schedule, even when you're not. Here's where you should be this May.

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
  • First harvests: lima beans

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Lima beans are a warm-season legume producing large, creamy beans with a buttery texture. Both bush and pole varieties are available, with pole types yielding more.

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 Lima 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 (95 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 8 – Jul 20
Recommended (50%) ✓ Fits season (93 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 28
Safe Start (90%) ✓ Fits season (89 days to spare)
Transplant: May 9 🍅 Harvest: Jul 11 – Aug 22

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 Lima Beans's growing requirements.

Soil pH

Your soil pH (5.7–6.8) overlaps with Lima Beans's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Lima Beans.

Organic Matter

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

How to Plant Lima Beans

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

Succession Planting Lima Beans

3
successive plantings in your 198-day season

Sow every 6.9 weeks. Last sowing by Jul 31 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.9″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 540 gal / 100 sq ft

Monthly Watering Guide for Lima Beans

Lima Beans needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Lima Beans Needs Rainfall You Supplement Action
Jan 6.4" 0" ❄️ Dormant
Feb 4.7" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 3.9" 2.6" 1.3" 💧 Light watering
May 3.9" 2.1" 1.8" 💧 Light watering
Jun 3.9" 1.5" 2.4" 🚿 Regular watering
Jul 3.9" 0.5" 3.4" 🚿 Regular watering
Aug 3.9" 0.6" 3.3" 🚿 Regular watering
Sep 3.9" 1.6" 2.3" 🚿 Regular watering
Oct 3.9" 3.5" 0.4" 💧 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.

Lima 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.

Lima Beans needs ~1,200 GDD — county provides 3,168 GDD Excellent fit

Lima Beans Planting Timeline — Jefferson County, WA

Lima Beans Planting Calendar

Activity When Date Range
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
March
April Direct Sow
May Direct Sow
June Harvest
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

198 days in Jefferson County

Growing Tips for Lima Beans in Jefferson County

Direct sow Lima Beans outdoors after April 14 in Jefferson County when soil has warmed and frost danger has passed.

Common pests for Lima 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 thoroughly warm at 65F or above. Do not soak seeds before planting as they may crack. Harvest when pods are plump but still green for fresh limas.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lima Beans in Jefferson County, WA?

Jefferson County is in Zone 8b with an average last frost of April 14. Plan your Lima 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.