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When to Plant Lima Beans in Franklin County, ID

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.

Franklin County, Idaho is in USDA Zone 5a. The average last spring frost is May 19 and the first fall frost is October 3, giving you a growing season of approximately 137 days.

At an elevation of 7,665 feet, Franklin County receives approximately 18.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Lima Beans during the growing season. With low rainfall, drip irrigation is essential for growing Lima Beans successfully. Mulch heavily to conserve soil moisture.

Franklin County, ID (Zone 5a) Short season
137 days
Last Spring Frost May 19
137 growing days
First Fall Frost October 3

Franklin County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Transplant: May 6 🍅 Harvest: Jul 8 – Aug 19
Recommended (50%) ✓ Fits season (32 days to spare)
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 1
Safe Start (90%) ✓ Fits season (25 days to spare)
Transplant: Jun 13 🍅 Harvest: Aug 15 – Sep 26

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 Franklin County

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

Soil pH

Your soil pH (6.7โ€“7.7) is more alkaline than Lima Beans prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Franklin County is excellent for Lima Beans โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Lima Beans.

How to Plant Lima Beans

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

Succession Planting Lima Beans

2
successive plantings in your 137-day season

Sow every 6.9 weeks. Last sowing by Jul 05 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 487 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

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 โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.1" 0" โ„๏ธ Dormant
Mar โ€” 1.5" 0" โ„๏ธ Dormant
Apr โ€” 2" 0" โ„๏ธ Dormant
May 3.9" 1.9" 2" ๐Ÿšฟ Regular watering
Jun 3.9" 1.3" 2.6" ๐Ÿšฟ Regular watering
Jul 3.9" 1.8" 2.1" ๐Ÿšฟ Regular watering
Aug 3.9" 2" 1.9" ๐Ÿ’ง Light watering
Sep 3.9" 1.6" 2.3" ๐Ÿšฟ Regular watering
Oct 3.9" 1.8" 2.1" ๐Ÿšฟ Regular watering
Nov โ€” 1.2" 0" โ„๏ธ Dormant
Dec โ€” 1.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Franklin County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,144 GDD — county provides 2,089 GDD Excellent fit

Lima Beans Planting Timeline โ€” Franklin County, ID

Lima Beans Planting Calendar

Activity When Date Range
Direct Sow May 26 May 26 โ€“ Jun 16
Harvest July 28 Jul 28 โ€“ Sep 8

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Direct Sow
June Direct Sow
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.9"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

137 days in Franklin County

Growing Tips for Lima Beans in Franklin County

Direct sow Lima Beans outdoors after May 19 in Franklin 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.

Franklin County receives only 18" of rain annually. Lima Beans needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

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 Franklin County, ID?

Franklin County is in Zone 5a with an average last frost of May 19. Plan your Lima Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Franklin County, ID?

Franklin County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 19 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Franklin County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Franklin County, ID. Local conditions may vary. Last updated: April 2026.