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When to Plant Scallions in Keweenaw County, MI

Scallions (green onions) are mild-flavored alliums harvested for their slender green tops and white bases. They are quick-growing and perfect for succession planting.

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 Scallions 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 (51 days to spare)
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Jul 10 – Aug 7
Recommended (50%) ✓ Fits season (51 days to spare)
Start indoors: Apr 7 Transplant: May 19 🍅 Harvest: Jul 14 – Aug 11
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Apr 23 Transplant: Jun 4 🍅 Harvest: Jul 30 – Aug 27

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
Scallions needs ~645 GDD — county provides 1,451 GDD Excellent fit

Scallions Planting Timeline โ€” Keweenaw County, MI

Scallions Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 โ€“ Apr 21
Transplant Outdoors May 19 May 19 โ€“ Jun 2
Direct Sow May 12 May 12 โ€“ Jun 2
Fall Sowing July 9 Jul 9 โ€“ Jul 23
Harvest July 14 Jul 14 โ€“ Aug 11

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Fall Sowing 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

50โ€“70 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4a

Growing Season

135 days

Growing Tips for Keweenaw County

Direct sow every 3 weeks for continuous harvest. Thin to 1 inch apart or grow in clusters. Harvest when pencil-thick by pulling or cutting at soil level.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

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Frequently Asked Questions

When should I plant Scallions in Keweenaw County, MI?

Keweenaw County is in Zone 4a with an average last frost of May 19. Plan your Scallions 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.