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When to Plant Christmas Lima Beans in Whitman County, WA

Whitman County, Washington Zone 6b May

May to-do list for Whitman County, Washington

A quick May briefing for Whitman County, Washington gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 10
Avg. first frost September 29
Soil temp (4") 59°F
Watering Critical
Pest pressure Low
Daylight 14.8 hrs
  1. Transplant christmas lima beans outside

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Put christmas lima beans seeds straight in the ground

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

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Christmas lima beans are a large, beautifully marbled heirloom bean with a rich, chestnut-like flavor. They are a climbing variety that produces generously in warm weather.

Whitman County, Washington is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is September 29, giving you a growing season of approximately 142 days.

At an elevation of 1,541 feet, Whitman County receives approximately 14.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Christmas Lima Beans during the growing season. With low rainfall, drip irrigation is essential for growing Christmas Lima Beans successfully. Mulch heavily to conserve soil moisture.

Whitman County, WA (Zone 6b) Short season
142 days
Last Spring Frost May 10
142 growing days
First Fall Frost September 29

Whitman County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Start indoors: Mar 4 Transplant: May 13 🍅 Harvest: Aug 5 – Sep 9
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Mar 15 Transplant: May 24 🍅 Harvest: Aug 16 – Sep 20
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: Apr 11 Transplant: Jun 20 🍅 Harvest: Sep 12 – Oct 17

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 Whitman County

How your county's soil matches Christmas Lima Beans's growing requirements.

Soil pH

Your soil pH (5.5–6.7) overlaps with Christmas Lima Beans's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Christmas Lima Beans will thrive.

How to Plant Christmas Lima Beans

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 722 gal / 100 sq ft

Monthly Watering Guide for Christmas Lima Beans

Christmas Lima 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 Christmas Lima Beans Needs Rainfall You Supplement Action
Jan 2.2" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 4.3" 0.8" 3.5" 🚿 Regular watering
Jun 4.3" 0.6" 3.7" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.2" 4.1" 🚿 Regular watering
Sep 4.3" 0.6" 3.7" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Whitman County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Christmas 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.

Christmas Lima Beans needs ~1,440 GDD — county provides 2,272 GDD Excellent fit

Christmas Lima Beans Planting Timeline — Whitman County, WA

Christmas Lima Beans Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest August 16 Aug 16 – Sep 20

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

142 days in Whitman County

Growing Tips for Christmas Lima Beans in Whitman County

Direct sow Christmas Lima Beans outdoors after May 10 in Whitman County when soil has warmed and frost danger has passed.

Common pests for Christmas Lima Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

Whitman County receives only 14" of rain annually. Christmas Lima Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil is warm. Provide tall trellising for vigorous vines. Harvest for fresh shelling when pods are plump or allow to dry on the vine for storage.

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 Christmas Lima Beans in Whitman County, WA?

Whitman County is in Zone 6b with an average last frost of May 10. Plan your Christmas Lima Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Whitman County, WA?

Whitman County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is September 29.

🌱

Your Whitman County Garden Planner — Free

A 24-page printable planner built for Whitman County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Whitman 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.