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When to Plant Leeks in Barron County, WI

Leeks are a mild, sweet allium that produces long white shanks. They are more refined than onions and are a key ingredient in soups, stews, and gratins.

Barron County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 17 and the first fall frost is September 25, giving you a growing season of approximately 131 days.

At an elevation of 1,256 feet, Barron County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Leeks to ensure they mature before fall.

Barron County, WI (Zone 4a) Short season
131 days
Last Spring Frost May 17
131 growing days
First Fall Frost September 25

Barron County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Aug 13 – Oct 8
Recommended (50%) ✗ May not fit
Start indoors: Apr 5 Transplant: May 17 🍅 Harvest: Aug 16 – Oct 11
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: Jun 1 🍅 Harvest: Aug 31 – Oct 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
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Leeks needs ~1,470 GDD — county provides 1,604 GDD Good fit

Leeks Planting Timeline โ€” Barron County, WI

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 โ€“ Apr 19
Transplant Outdoors May 17 May 17 โ€“ May 31
Direct Sow May 10 May 10 โ€“ May 31
Fall Sowing July 3 Jul 3 โ€“ Jul 17
Harvest August 16 Aug 16 โ€“ Oct 11

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May Transplant Outdoors Direct Sow
June โ€”
July Fall Sowing
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“150 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4a

Growing Season

131 days

Growing Tips for Barron County

Start seeds indoors 10-12 weeks before last frost. Transplant into trenches and hill soil around stems as they grow to increase the white portion. Harvest as needed.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Level Up Your Garden

Frequently Asked Questions

When should I plant Leeks in Barron County, WI?

Barron County is in Zone 4a with an average last frost of May 17. Plan your Leeks planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Barron County, WI?

Barron County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 17 and first fall frost is September 25.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Barron 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 Barron County, WI. Local conditions may vary. Last updated: April 2026.