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When to plant Leeks in Au Gres, MI

Au Gres's spring Leeks window runs April 28 through May 19. time plantings around the expected last-frost window for best survival. A second sowing from July 28 to August 11 extends the harvest into fall.

When to Plant Leeks in Au Gres, MI

Leeks
Arenac County, Michigan Zone 5b July

July to-do list for Arenac County, Michigan

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

Avg. last frost May 12
Avg. first frost October 6
Soil temp (4") 78°F
Watering Moderate
Pest pressure High
Daylight 15 hrs
  1. Plant your fall garden: leeks

    Fall crops get sweeter with a light frost. Don't be afraid of cool nights.

To set up a strong August, finish these tasks
  • First harvests: 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.

Au Gres, Michigan is in USDA Zone 5b. The average last spring frost is May 12 and the first fall frost is October 6, giving you a growing season of approximately 147 days.

At an elevation of 1,015 feet, Arenac County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Leeks during the growing season.

Au Gres, MI (Zone 5b) Short season
147 days
Last Spring Frost May 12
147 growing days
First Fall Frost October 6

Au Gres Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Aug 5 – Oct 21
Recommended (50%) ✗ May not fit
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Aug 11 – Oct 27
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: May 25 🍅 Harvest: Aug 24 – Nov 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 Au Gres

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

Soil pH

Your soil pH (6.2–7.1) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Arenac 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 10 weeks before your first frost date for a fall harvest.

Leeks Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 221 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 2.2" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 3.5" 3.9" 0" ✅ Rainfall sufficient
Jun 3.5" 3.9" 0" ✅ Rainfall sufficient
Jul 3.5" 3.6" 0" ✅ Rainfall sufficient
Aug 3.5" 3.2" 0.3" 💧 Light watering
Sep 3.5" 2.6" 0.9" 💧 Light watering
Oct 3.5" 2.2" 1.3" 💧 Light watering
Nov 2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Arenac 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 2,131 GDD Good fit

Leeks Planting Timeline — Au Gres, MI

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 – Apr 21
Transplant Outdoors May 12 May 12 – May 26
Direct Sow April 28 Apr 28 – May 19
Harvest August 11 Aug 11 – Oct 27
Fall Sowing July 28 Jul 28 – Aug 11

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 · Only during dry spells

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

147 days in Arenac County

Growing Tips for Leeks in Au Gres

Direct sow Leeks outdoors after May 12 in Arenac County when soil has warmed and frost danger has passed.

Your 147.0-day growing season in Arenac 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 →

When should I plant Leeks in Au Gres, MI?

In Au Gres, MI, plant Leeks after the last frost (around May 12) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Au Gres, MI for Leeks?

Au Gres sits in USDA Zone 5b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.

Can Leeks grow in Au Gres's climate?

Yes — Leeks grows well in Au Gres's temperate climate. Au Gres averages a 147-day frost-free season, with last frost around May 12 and first frost around October 6.

🌱

Your Arenac County Garden Planner — Free

A 22-page printable planner built for Arenac 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 Arenac County, MI. Local conditions may vary. Last updated: July 2026.