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When to Plant Leeks in Whitley County, IN

Whitley County, Indiana Zone 6a May

What to do in May

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

Avg. last frost April 27
Avg. first frost October 16
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
Looking ahead to 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.

Whitley County, Indiana is in USDA Zone 6a. The average last spring frost is April 27 and the first fall frost is October 16, giving you a growing season of approximately 172 days.

At an elevation of 584 feet, Whitley County receives approximately 32.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Leeks to ensure they mature before fall.

Whitley County, IN (Zone 6a) Moderate season
172 days
Last Spring Frost April 27
172 growing days
First Fall Frost October 16

Whitley County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (4 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jul 22 – Oct 7
Recommended (50%) ✓ Fits season (4 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jul 27 – Oct 12
Safe Start (90%) ✗ May not fit
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Aug 12 – Oct 28

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 Whitley County

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

Soil pH

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

Soil Texture

The silt loam soil in Whitley 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 (4.1%) — 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.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 373 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" 0" ❄️ Dormant
Apr 3.5" 2.9" 0.6" 💧 Light watering
May 3.5" 3.4" 0.1" 💧 Light watering
Jun 3.5" 4.6" 0" ✅ Rainfall sufficient
Jul 3.5" 3.8" 0" ✅ Rainfall sufficient
Aug 3.5" 3.5" 0" ✅ Rainfall sufficient
Sep 3.5" 2.9" 0.6" 💧 Light watering
Oct 3.5" 2.6" 0.9" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Whitley 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 ~1,470 GDD — county provides 2,107 GDD Excellent fit

Leeks Planting Timeline — Whitley County, IN

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 13 Apr 13 – May 4
Harvest July 27 Jul 27 – Oct 12
Fall Sowing August 7 Aug 7 – Aug 21

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 Harvest
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 6a

📆 Growing Season

172 days in Whitley County

Growing Tips for Leeks in Whitley County

Direct sow Leeks outdoors after April 27 in Whitley 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 →

Frequently Asked Questions

When should I plant Leeks in Whitley County, IN?

Whitley County is in Zone 6a with an average last frost of April 27. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Whitley County, IN?

Whitley County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 27 and first fall frost is October 16.

🌱

Your Whitley County Garden Planner — Free

A 24-page printable planner built for Whitley 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 Whitley County, IN. 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.