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When to Plant Leeks in Outagamie 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.

Outagamie County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 8 and the first fall frost is October 5, giving you a growing season of approximately 150 days.

At an elevation of 1,052 feet, Outagamie County receives approximately 36.7 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.

Outagamie County, WI (Zone 4b) Moderate season
150 days
Last Spring Frost May 8
150 growing days
First Fall Frost October 5

Outagamie County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Start indoors: Mar 18 Transplant: Apr 29 🍅 Harvest: Jul 29 – Sep 23
Recommended (50%) ✓ Fits season (3 days to spare)
Start indoors: Mar 27 Transplant: May 8 🍅 Harvest: Aug 7 – Oct 2
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: Apr 9 Transplant: May 21 🍅 Harvest: Aug 20 – Oct 15

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.

Soil Compatibility in Outagamie County

How your county's soil matches Leeks's growing requirements.

Soil pH

Your soil pH (6.3โ€“6.8) is within Leeks's preferred range (6.0โ€“7.0).

Soil Texture

The silt loam soil in Outagamie County is excellent for Leeks โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.6%) โ€” Leeks will thrive.

How to Plant Leeks

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Leeks

Leeks needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Leeks Needs Rainfall You Supplement Action
Jan โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.6" 0" โ„๏ธ Dormant
Mar โ€” 2.8" 0" โ„๏ธ Dormant
Apr โ€” 3.5" 0" โ„๏ธ Dormant
May 3.5" 4.8" 0" โœ… Rainfall sufficient
Jun 3.5" 3.9" 0" โœ… Rainfall sufficient
Jul 3.5" 4.1" 0" โœ… Rainfall sufficient
Aug 3.5" 3.3" 0.2" ๐Ÿ’ง Light watering
Sep 3.5" 3.5" 0" โœ… Rainfall sufficient
Oct 3.5" 3" 0.5" ๐Ÿ’ง Light watering
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 1.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Outagamie County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Leeks Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Leeks needs ~1,470 GDD — county provides 1,837 GDD Good fit

Leeks Planting Timeline โ€” Outagamie County, WI

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 โ€“ Apr 10
Transplant Outdoors May 8 May 8 โ€“ May 22
Direct Sow May 1 May 1 โ€“ May 22
Harvest August 7 Aug 7 โ€“ Oct 2
Fall Sowing July 13 Jul 13 โ€“ Jul 27

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
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

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

90โ€“150 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

150 days in Outagamie County

Growing Tips for Leeks in Outagamie County

Direct sow Leeks outdoors after May 08 in Outagamie County when soil has warmed and frost danger has passed.

Your 150.0-day growing season in Outagamie County is tight for Leeks (90.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Leeks in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Leeks in Outagamie County, WI?

Outagamie County is in Zone 4b with an average last frost of May 8. Plan your Leeks planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Outagamie County, WI?

Outagamie County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 8 and first fall frost is October 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Outagamie County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Outagamie County, WI. Local conditions may vary. Last updated: April 2026.