When to Plant Leeks in DuPage 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.
DuPage County, Illinois is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 17, giving you a growing season of approximately 177 days.
At an elevation of 803 feet, DuPage County receives approximately 31 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.
DuPage County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.7
Drainage
Well Drained
Monthly Watering Guide for Leeks
Leeks needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Leeks Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3" | 1.3" | 💧 Light watering |
| May | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Aug | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Sep | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Oct | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in DuPage County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Leeks Planting Timeline — DuPage County, IL
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 19 | Mar 19 – Apr 2 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 9 | Apr 9 – Apr 30 |
| Harvest | July 23 | Jul 23 – Oct 8 |
| Fall Sowing | August 8 | Aug 8 – Aug 22 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
177 days in DuPage County
Growing Tips for DuPage County
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
Check more plant combinations with our Companion Planting Checker →
Leeks in Other Locations
Frequently Asked Questions
When should I plant Leeks in DuPage County, IL?
DuPage County is in Zone 5b with an average last frost of April 23. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is DuPage County, IL?
DuPage County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 17.
Plan Your Garden with Confidence
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