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When to Plant Leeks in Saline County, IL

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.

Saline County, Illinois is in USDA Zone 6b. The average last spring frost is April 8 and the first fall frost is October 24, giving you a growing season of approximately 199 days.

At an elevation of 748 feet, Saline County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Leeks during the growing season.

Saline County, IL (Zone 6b) Moderate season
199 days
Last Spring Frost April 8
199 growing days
First Fall Frost October 24

Saline County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Feb 28 Transplant: Apr 4 🍅 Harvest: Jul 4 – Sep 19
Recommended (50%) ✓ Fits season (31 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: Jul 8 – Sep 23
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Jul 21 – Oct 6

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 Saline County

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

Soil pH

Your soil pH (6.0โ€“6.7) is within Leeks's preferred range (6.0โ€“7.0).

Soil Texture

The silt loam soil in Saline County is excellent for Leeks โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Leeks.

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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Leeks needs ~1,920 GDD — county provides 3,184 GDD Excellent fit

Leeks Planting Timeline โ€” Saline County, IL

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 โ€“ Mar 18
Transplant Outdoors April 8 Apr 8 โ€“ Apr 22
Direct Sow March 25 Mar 25 โ€“ Apr 15
Fall Sowing August 15 Aug 15 โ€“ Aug 29
Harvest July 8 Jul 8 โ€“ Sep 23

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

90โ€“150 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

199 days in Saline County

Growing Tips for Leeks in Saline County

Direct sow Leeks outdoors after April 08 in Saline 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Leeks in Saline County, IL?

Saline County is in Zone 6b with an average last frost of April 8. Plan your Leeks planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Saline County, IL?

Saline County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 8 and first fall frost is October 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Saline County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Saline County, IL. Local conditions may vary. Last updated: April 2026.