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When to Plant Leeks in Burnett County, WI

Burnett County, Wisconsin Zone 4a May

May to-do list for Burnett County, Wisconsin

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 15
Avg. first frost September 27
Soil temp (4") 50°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Transplant leeks outside

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Seed leeks outdoors

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

Get ahead of June
  • 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.

Burnett County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 15 and the first fall frost is September 27, giving you a growing season of approximately 135 days.

At an elevation of 574 feet, Burnett County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Leeks to ensure they mature before fall.

Burnett County, WI (Zone 4a) Short season
135 days
Last Spring Frost May 15
135 growing days
First Fall Frost September 27
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Burnett County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 28 Transplant: May 9 🍅 Harvest: Aug 8 – Oct 3
Recommended (50%) ✗ May not fit
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Aug 14 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: Apr 18 Transplant: May 30 🍅 Harvest: Aug 29 – Oct 24

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 Burnett County

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

Soil pH

Your soil pH (6.2–7.3) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Leeks.

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 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 109 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 3.5" 3.6" 0" ✅ Rainfall sufficient
Jun 3.5" 4.2" 0" ✅ Rainfall sufficient
Jul 3.5" 3" 0.5" 💧 Light watering
Aug 3.5" 3.6" 0" ✅ Rainfall sufficient
Sep 3.5" 2.7" 0.8" 💧 Light watering
Oct 2.5" 0" ❄️ Dormant
Nov 2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Burnett 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 ~1,110 GDD — county provides 1,248 GDD Good fit

Leeks Planting Timeline — Burnett County, WI

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest August 14 Aug 14 – Oct 9
Fall Sowing July 5 Jul 5 – Jul 19

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

135 days in Burnett County

Growing Tips for Leeks in Burnett County

Direct sow Leeks outdoors after May 15 in Burnett County when soil has warmed and frost danger has passed.

Your 135.0-day growing season in Burnett 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 Burnett County, WI?

Burnett County is in Zone 4a with an average last frost of May 15. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Burnett County, WI?

Burnett County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 15 and first fall frost is September 27.

🌱

Your Burnett County Garden Planner — Free

A 24-page printable planner built for Burnett County (Zone 4a). 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 Burnett 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.