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When to Plant Leeks in Outagamie County, WI

Outagamie County, Wisconsin Zone 5b May

Your May game plan for Outagamie County, Wisconsin

May is a pivotal month for Outagamie County, Wisconsin gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 8
Avg. first frost October 5
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Move leeks from tray to bed

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

Coming up in June — start thinking about
  • Starting indoors: leeks

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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 5b. 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 83°F, so choose short-season varieties of Leeks to ensure they mature before fall.

Outagamie County, WI (Zone 5b) 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) ✗ May not fit
Start indoors: Mar 25 Transplant: Apr 29 🍅 Harvest: Jul 29 – Oct 14
Recommended (50%) ✗ May not fit
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Aug 7 – Oct 23
Safe Start (90%) ✗ May not fit
Start indoors: Apr 16 Transplant: May 21 🍅 Harvest: Aug 20 – Nov 5

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 (6.3–6.8) is within Leeks's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — Leeks will thrive.

How to Plant Leeks

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

Fall planting: Sow 10 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 — 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 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 3.5" 4.8" 0" ✅ Rainfall sufficient
Jun 3.5" 3.9" 0" ✅ Rainfall sufficient
Jul 3.5" 4.1" 0" ✅ Rainfall sufficient
Aug 3.5" 3.3" 0.2" 💧 Light watering
Sep 3.5" 3.5" 0" ✅ Rainfall sufficient
Oct 3.5" 3" 0.5" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Outagamie County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 — Outagamie County, WI

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors May 8 May 8 – May 22
Direct Sow April 24 Apr 24 – May 15
Harvest August 7 Aug 7 – Oct 23
Fall Sowing July 27 Jul 27 – Aug 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 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 5b with an average last frost of May 8. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Outagamie County, WI?

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

🌱

Your Outagamie County Garden Planner — Free

A 24-page printable planner built for Outagamie County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Outagamie County, WI. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.