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When to Plant Lima Beans in Ada 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.

Ada County, Idaho is in USDA Zone 6b. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.

At an elevation of 4,372 feet, Ada County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90ยฐF, 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.

Ada County, ID (Zone 6b) Moderate season
176 days
Last Spring Frost April 23
176 growing days
First Fall Frost October 16

Ada County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (73 days to spare)
Transplant: Apr 15 🍅 Harvest: Jun 17 – Jul 29
Recommended (50%) ✓ Fits season (71 days to spare)
Transplant: Apr 23 🍅 Harvest: Jun 25 – Aug 6
Safe Start (90%) ✓ Fits season (69 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Aug 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 992 gal / 100 sq ft
Drought risk

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

Lima Beans needs ~1,312 GDD — county provides 3,080 GDD Excellent fit

Lima Beans Planting Timeline โ€” Ada County, ID

Lima Beans Planting Calendar

Activity When Date Range
Direct Sow April 30 Apr 30 โ€“ May 21
Harvest July 2 Jul 2 โ€“ Aug 13

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6b

Growing Season

176 days

Growing Tips for Ada County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Lima Beans in Ada County, ID?

Ada County is in Zone 6b with an average last frost of April 23. Plan your Lima Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ada County, ID?

Ada County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is April 23 and first fall frost is October 16.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Ada County gardeners in Zone 6b 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 Ada County, ID. Local conditions may vary. Last updated: April 2026.