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When to plant Leeks in Sibley County County,

Spring Leeks in Sibley County County goes in April 23–May 14, once nighttime temps stop dipping near freezing. A second sowing from July 12 to July 26 extends the harvest into fall.

When to Plant Leeks in Sibley County, MN

Leeks
Sibley County, Minnesota Zone 4b June

June to-do list for Sibley County, Minnesota

Each item below is timed to Sibley County, Minnesota's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 30
Avg. first frost October 4
Soil temp (4") 65°F
Watering Low
Pest pressure High
Daylight 15.3 hrs
  1. Get leeks seeds going inside

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

A few tasks this June that'll pay off in July
  • First harvests: 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.

Sibley County, Minnesota is in USDA Zone 4b. The average last spring frost is April 30 and the first fall frost is October 4, giving you a growing season of approximately 157 days.

At an elevation of 1,364 feet, Sibley County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Leeks to ensure they mature before fall.

Sibley County, MN (Zone 4b) Moderate season
157 days
Last Spring Frost April 30
157 growing days
First Fall Frost October 4
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Sibley County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Start indoors: Mar 13 Transplant: Apr 24 🍅 Harvest: Jul 24 – Sep 18
Recommended (50%) ✓ Fits season (10 days to spare)
Start indoors: Mar 19 Transplant: Apr 30 🍅 Harvest: Jul 30 – Sep 24
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Aug 14 – Oct 9

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 Sibley County

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

Soil pH

Your soil pH (6.1–6.9) is within Leeks's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — 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.

Leeks Water Budget

Plant needs
0.8″/week
Rainfall provides
1.1″/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 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.5" 3.6" 0" ✅ Rainfall sufficient
May 3.5" 5" 0" ✅ Rainfall sufficient
Jun 3.5" 5.3" 0" ✅ Rainfall sufficient
Jul 3.5" 4.9" 0" ✅ Rainfall sufficient
Aug 3.5" 3.7" 0" ✅ Rainfall sufficient
Sep 3.5" 3.7" 0" ✅ Rainfall sufficient
Oct 3.5" 3.2" 0.3" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sibley 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 ~1,380 GDD — county provides 1,805 GDD Excellent fit

Leeks Planting Timeline — Sibley County, MN

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 23 Apr 23 – May 14
Harvest July 30 Jul 30 – Sep 24
Fall Sowing July 12 Jul 12 – Jul 26

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Fall Sowing Harvest
August Harvest
September Harvest
October
November
December
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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 4b

📆 Growing Season

157 days in Sibley County

Growing Tips for Leeks in Sibley County

Direct sow Leeks outdoors after April 30 in Sibley County when soil has warmed and frost danger has passed.

Your 157.0-day growing season in Sibley 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 Sibley County, MN?

Sibley County is in Zone 4b with an average last frost of April 30. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sibley County, MN?

Sibley County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 30 and first fall frost is October 4.

When should I plant Leeks in Sibley County, ?

In Sibley County, , plant Leeks after the last frost (around April 30) and before the first frost (around October 4). Best results when soil holds above 50°F.

What growing zone is Sibley County, for Leeks?

Sibley County sits in USDA Zone 4b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.

Can Leeks grow in Sibley County's climate?

Yes — Leeks grows well in Sibley County's temperate climate. Sibley County averages a 157-day frost-free season, with last frost around April 30 and first frost around October 4.

🌱

Your Sibley County Garden Planner — Free

A 22-page printable planner built for Sibley County (Zone 4b). 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 Sibley County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

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