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When to Plant Lima Beans in Keweenaw County, MI

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.

Keweenaw County, Michigan is in USDA Zone 4a. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.

At an elevation of 1,035 feet, Keweenaw County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Lima Beans to ensure they mature before fall.

Keweenaw County, MI (Zone 4a) Short season
135 days
Last Spring Frost May 19
135 growing days
First Fall Frost October 1

Keweenaw County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Transplant: May 15 🍅 Harvest: Jul 17 – Aug 28
Recommended (50%) ✓ Fits season (30 days to spare)
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 1
Safe Start (90%) ✓ Fits season (29 days to spare)
Transplant: Jun 4 🍅 Harvest: Aug 6 – Sep 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Lima Beans needs ~806 GDD — county provides 1,451 GDD Excellent fit

Lima Beans Planting Timeline โ€” Keweenaw County, MI

Lima Beans Planting Calendar

Activity When Date Range
Direct Sow June 2 Jun 2 โ€“ Jun 23
Harvest August 4 Aug 4 โ€“ Sep 15

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June Direct Sow
July โ€”
August Harvest
September Harvest
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 4a

Growing Season

135 days

Growing Tips for Keweenaw 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

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Frequently Asked Questions

When should I plant Lima Beans in Keweenaw County, MI?

Keweenaw County is in Zone 4a 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 Keweenaw County, MI?

Keweenaw County, Michigan is in USDA Hardiness Zone 4a. The average last spring frost is May 19 and first fall frost is October 1.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Keweenaw County gardeners in Zone 4a 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 Keweenaw County, MI. Local conditions may vary. Last updated: April 2026.