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When to Plant Lima Beans in Lemhi County, ID

Lemhi County, Idaho Zone 4b April

Your April planting checklist for Lemhi County, Idaho

April rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Lemhi County, Idaho.

Avg. last frost June 9
Avg. first frost September 14
Soil temp (4") 20°F
Watering High
Pest pressure Low
Daylight 13.3 hrs

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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.

Lemhi County, Idaho is in USDA Zone 4b. The average last spring frost is June 9 and the first fall frost is September 14, giving you a growing season of approximately 97 days.

At an elevation of 6,743 feet, Lemhi County receives approximately 12.6 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Lima Beans to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Lima Beans successfully. Mulch heavily to conserve soil moisture.

Lemhi County, ID (Zone 4b) Very short season
97 days
Last Spring Frost June 9
97 growing days
First Fall Frost September 14
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Lemhi County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Transplant: May 14 🍅 Harvest: Jul 16 – Aug 27
Recommended (50%) ✗ May not fit
Transplant: Jun 9 🍅 Harvest: Aug 11 – Sep 22
Safe Start (90%) ✗ May not fit
Transplant: Jun 25 🍅 Harvest: Aug 27 – Oct 8

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 Lemhi County

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

Soil pH

Your soil pH (6.2–8.2) is more alkaline than Lima Beans prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Lima Beans.

How to Plant Lima Beans

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

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 367 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.8" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 1.4" 0" ❄️ Dormant
Jun 3.9" 0.8" 3.1" 🚿 Regular watering
Jul 3.9" 1.3" 2.6" 🚿 Regular watering
Aug 3.9" 1.3" 2.6" 🚿 Regular watering
Sep 3.9" 1.2" 2.7" 🚿 Regular watering
Oct 1" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Lemhi 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 ~975 GDD — county provides 1,261 GDD Good fit

Lima Beans Planting Timeline — Lemhi County, ID

Lima Beans Planting Calendar

Activity When Date Range
Direct Sow June 23 Jun 23 – Jul 14
Harvest August 25 Aug 25 – Oct 6

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Direct Sow
July Direct Sow
August Harvest
September Harvest
October Harvest
November
December
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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: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

97 days in Lemhi County

Growing Tips for Lima Beans in Lemhi County

Direct sow Lima Beans outdoors after June 09 in Lemhi County when soil has warmed and frost danger has passed.

Your 97.0-day growing season in Lemhi County is tight for Lima Beans (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Lemhi County receives only 13" of rain annually. Lima Beans needs consistent moisture — 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 Lemhi County, ID?

Lemhi County is in Zone 4b with an average last frost of June 9. Plan your Lima Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lemhi County, ID?

Lemhi County, Idaho is in USDA Hardiness Zone 4b. The average last spring frost is June 9 and first fall frost is September 14.

🌱

Your Lemhi County Garden Planner — Free

A 24-page printable planner built for Lemhi County (Zone 4b). 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 Lemhi County, ID. Local conditions may vary. Last updated: April 2026.

Sources & credits

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