When to plant Leeks in Dover,
In Dover, plant Leeks in spring between April 8 and April 29, once soil temps hold above 50°F. Dover's last frost averages April 22, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between August 5 and August 19 — roughly 150 days before the first frost on October 14.
When to Plant Leeks in Dover, IL
This month in Dover, IL
Here's what deserves your attention in Dover, IL this month. Everything below is tailored to Zone 5b and timed around your local frost dates.
Looking ahead to July
- First harvests: leeks
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.
Dover, Illinois is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 14, giving you a growing season of approximately 175 days.
At an elevation of 613 feet, Bureau County receives approximately 34.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Leeks to ensure they mature before fall.
Dover Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-6.7
Drainage
Well Drained
Leeks Planting Risk Windows
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 Dover
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.3–6.7) is within Leeks's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Bureau County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.1%) — Leeks will thrive.
How to Plant Leeks
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Leeks Water Budget
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 | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 3.5" | 3.2" | 0.3" | 💧 Light watering |
| May | 3.5" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 3.5" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 4" | 0" | ✅ Rainfall sufficient |
| Aug | 3.5" | 3.3" | 0.2" | 💧 Light watering |
| Sep | 3.5" | 2.8" | 0.7" | 💧 Light watering |
| Oct | 3.5" | 2.7" | 0.8" | 💧 Light watering |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Bureau 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 Planting Timeline — Dover, IL
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 18 | Mar 18 – Apr 1 |
| Transplant Outdoors | April 22 | Apr 22 – May 6 |
| Direct Sow | April 8 | Apr 8 – Apr 29 |
| Harvest | July 22 | Jul 22 – Oct 7 |
| Fall Sowing | August 5 | Aug 5 – Aug 19 |
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
0.8"/week · Natural rainfall sufficient
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
175 days in Bureau County
Growing Tips for Leeks in Dover
Direct sow Leeks outdoors after April 22 in Bureau 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
Check more plant combinations with our Companion Planting Checker →
Leeks in Other Locations
When should I plant Leeks in Dover, ?
In Dover, , plant Leeks after the last frost (around April 22) and before the first frost (around October 14). Best results when soil holds above 50°F.
What growing zone is Dover, for Leeks?
Dover sits in USDA Zone 5b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.
Can Leeks grow in Dover's climate?
Yes — Leeks grows well in Dover's temperate climate. Dover averages a 175-day frost-free season, with last frost around April 22 and first frost around October 14.
Your Bureau County Garden Planner — Free
A 22-page printable planner built for Bureau 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.