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When to Plant Lima Beans in Boise County, ID

Boise County, Idaho Zone 7a May

Top priorities for Boise County, Idaho gardeners in May

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

Avg. last frost May 18
Avg. first frost September 27
Soil temp (4") 34°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
  1. Outdoor sowing time: lima beans

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

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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.

Boise County, Idaho is in USDA Zone 7a. The average last spring frost is May 18 and the first fall frost is September 27, giving you a growing season of approximately 132 days.

At an elevation of 8,023 feet, Boise County receives approximately 24.3 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Lima Beans during the growing season.

Boise County, ID (Zone 7a) Short season
132 days
Last Spring Frost May 18
132 growing days
First Fall Frost September 27

Boise 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 (23 days to spare)
Transplant: May 5 🍅 Harvest: Jul 7 – Aug 18
Recommended (50%) ✓ Fits season (27 days to spare)
Transplant: May 18 🍅 Harvest: Jul 20 – Aug 31
Safe Start (90%) ✓ Fits season (26 days to spare)
Transplant: Jun 16 🍅 Harvest: Aug 18 – Sep 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 Boise County

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

Soil pH

Your soil pH (6.7–7.7) 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 Boise County is excellent for Lima Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). 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 132-day season

Sow every 6.9 weeks. Last sowing by Jun 29 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 179 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.8" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 3.9" 3" 0.9" 💧 Light watering
Jun 3.9" 1.9" 2" 🚿 Regular watering
Jul 3.9" 1.8" 2.1" 🚿 Regular watering
Aug 3.9" 2.8" 1.1" 💧 Light watering
Sep 3.9" 1.7" 2.2" 🚿 Regular watering
Oct 2.4" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Boise 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 ~1,088 GDD — county provides 1,914 GDD Excellent fit

Lima Beans Planting Timeline — Boise County, ID

Lima Beans Planting Calendar

Activity When Date Range
Direct Sow May 25 May 25 – Jun 15
Harvest July 27 Jul 27 – Sep 7

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

132 days in Boise County

Growing Tips for Lima Beans in Boise County

Direct sow Lima Beans outdoors after May 18 in Boise 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.

Boise County receives only 24" 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 Boise County, ID?

Boise County is in Zone 7a with an average last frost of May 18. Plan your Lima Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boise County, ID?

Boise County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is May 18 and first fall frost is September 27.

🌱

Your Boise County Garden Planner — Free

A 24-page printable planner built for Boise County (Zone 7a). 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 Boise County, ID. 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.