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When to Plant Onion in Lake of the Woods County, MN

Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

Lake of the Woods County, Minnesota is in USDA Zone 3a. The average last spring frost is May 19 and the first fall frost is September 22, giving you a growing season of approximately 126 days.

At an elevation of 1,032 feet, Lake of the Woods County receives approximately 32.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Onion to ensure they mature before fall.

Lake of the Woods County, MN (Zone 3a) Short season
126 days
Last Spring Frost May 19
126 growing days
First Fall Frost September 22

Lake of the Woods County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Aug 13 – Sep 17
Recommended (50%) ✓ Fits season (0 days to spare)
Start indoors: Apr 7 Transplant: May 19 🍅 Harvest: Aug 18 – Sep 22
Safe Start (90%) ✓ Fits season (0 days to spare)
Start indoors: Apr 22 Transplant: Jun 3 🍅 Harvest: Sep 2 – Oct 7

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
1.1″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 228 gal / 100 sq ft
Onion needs ~1,050 GDD — county provides 1,260 GDD Good fit

Onion Planting Timeline โ€” Lake of the Woods County, MN

Onion 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 June 30 Jun 30 โ€“ Jul 14
Harvest August 18 Aug 18 โ€“ Sep 22

Plant 1" 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 Fall Sowing
July Fall Sowing
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

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 3a

Growing Season

126 days

Growing Tips for Lake of the Woods County

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

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Frequently Asked Questions

When should I plant Onion in Lake of the Woods County, MN?

Lake of the Woods County is in Zone 3a with an average last frost of May 19. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lake of the Woods County, MN?

Lake of the Woods County, Minnesota is in USDA Hardiness Zone 3a. The average last spring frost is May 19 and first fall frost is September 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lake of the Woods County gardeners in Zone 3a 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 Lake of the Woods County, MN. Local conditions may vary. Last updated: April 2026.