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When to Plant Leeks in Lake County, MN

Lake County, Minnesota Zone 4a May

What to do in May

We've pulled the most time-sensitive tasks for Lake County, Minnesota this May and put them front and centre. Tackle them in order.

Avg. last frost June 1
Avg. first frost September 12
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 14.9 hrs
  1. Plant leeks from seed, right in the garden

    These tolerate cool soil, so you're not gambling by sowing now.

Looking ahead to June
  • Transplants going out: leeks
  • Fall sowing: 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.

Lake County, Minnesota is in USDA Zone 4a. The average last spring frost is June 1 and the first fall frost is September 12, giving you a growing season of approximately 103 days.

At an elevation of 1,191 feet, Lake County receives approximately 36.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Leeks to ensure they mature before fall.

Lake County, MN (Zone 4a) Short season
103 days
Last Spring Frost June 1
103 growing days
First Fall Frost September 12

Lake County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: Aug 19 – Oct 14
Recommended (50%) ✗ May not fit
Start indoors: Apr 20 Transplant: Jun 1 🍅 Harvest: Aug 31 – Oct 26
Safe Start (90%) ✗ May not fit
Start indoors: May 7 Transplant: Jun 18 🍅 Harvest: Sep 17 – Nov 12

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 Lake County

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

Soil pH

Your soil pH (5.9–6.8) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Lake 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 (5.1%) — 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
1.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 4.6" 0" ❄️ Dormant
Jun 3.5" 5.2" 0" ✅ Rainfall sufficient
Jul 3.5" 3.9" 0" ✅ Rainfall sufficient
Aug 3.5" 4.2" 0" ✅ Rainfall sufficient
Sep 3.5" 3" 0.5" 💧 Light watering
Oct 2.4" 0" ❄️ Dormant
Nov 2.3" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Lake 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 ~1,290 GDD — county provides 1,107 GDD May not mature

Leeks Planting Timeline — Lake County, MN

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 20 Apr 20 – May 4
Transplant Outdoors June 1 Jun 1 – Jun 15
Direct Sow May 25 May 25 – Jun 15
Harvest August 31 Aug 31 – Oct 26
Fall Sowing June 20 Jun 20 – Jul 4

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Direct Sow
June Transplant Outdoors Direct Sow Fall Sowing
July Fall Sowing
August 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: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

103 days in Lake County

Growing Tips for Leeks in Lake County

Direct sow Leeks outdoors after June 01 in Lake County when soil has warmed and frost danger has passed.

Your 103.0-day growing season in Lake 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 Lake County, MN?

Lake County is in Zone 4a with an average last frost of June 1. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake County, MN?

Lake County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is June 1 and first fall frost is September 12.

🌱

Your Lake County Garden Planner — Free

A 24-page printable planner built for Lake 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 Lake County, MN. 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.