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When to plant Leeks in Pullman,

Plant Leeks in Pullman from April 18 to May 9 in spring. Pullman sits in USDA Zone 6a, with last frost around May 2 and first frost on October 14. A second sowing from August 5 to August 19 extends the harvest into fall.

When to Plant Leeks in Pullman, MI

Leeks
Pullman, MI Zone 6a June

June to-do list for Pullman, MI

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Pullman, MI.

Avg. last frost May 2
Avg. first frost October 14
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Fire up the seed-starting tray: leeks

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

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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.

Pullman, Michigan is in USDA Zone 6a. The average last spring frost is May 2 and the first fall frost is October 14, giving you a growing season of approximately 165 days.

At an elevation of 1,257 feet, Allegan County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Leeks during the growing season.

Pullman, MI (Zone 6a) Moderate season
165 days
Last Spring Frost May 2
165 growing days
First Fall Frost October 14
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Pullman Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.7

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jul 27 – Oct 12
Recommended (50%) ✗ May not fit
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Aug 1 – Oct 17
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 Pullman

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

Soil pH

Your soil pH (6.2–6.7) is within Leeks's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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.

Leeks Water Budget

Plant needs
0.8″/week
Rainfall provides
1.0″/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 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 3.5" 3.5" 0" ✅ Rainfall sufficient
Jun 3.5" 4.9" 0" ✅ Rainfall sufficient
Jul 3.5" 4.2" 0" ✅ Rainfall sufficient
Aug 3.5" 3.4" 0.1" 💧 Light watering
Sep 3.5" 3.6" 0" ✅ Rainfall sufficient
Oct 3.5" 3.1" 0.4" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Allegan 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 ~1,740 GDD — county provides 2,392 GDD Excellent fit

Leeks Planting Timeline — Pullman, MI

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 18 Apr 18 – May 9
Harvest August 1 Aug 1 – Oct 17
Fall Sowing August 5 Aug 5 – Aug 19

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June
July
August Fall Sowing Harvest
September Harvest
October Harvest
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 6a

📆 Growing Season

165 days in Allegan County

Growing Tips for Leeks in Pullman

Direct sow Leeks outdoors after May 02 in Allegan County when soil has warmed and frost danger has passed.

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 →

When should I plant Leeks in Pullman, ?

In Pullman, , plant Leeks after the last frost (around May 2) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Pullman, for Leeks?

Pullman sits in USDA Zone 6a. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.

Can Leeks grow in Pullman's climate?

Yes — Leeks grows well in Pullman's temperate climate. Pullman averages a 165-day frost-free season, with last frost around May 2 and first frost around October 14.

🌱

Your Allegan County Garden Planner — Free

A 22-page printable planner built for Allegan County (Zone 6a). 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 Allegan County, MI. Local conditions may vary. Last updated: June 2026.