When to plant Leeks in Robinson, IL
Spring Leeks in Robinson goes in March 31–April 21, once nighttime temps stop dipping near freezing. A second sowing from August 14 to August 28 extends the harvest into fall.
When to Plant Leeks in Robinson, IL
June in Crawford County, Illinois — your action list
Your Crawford County, Illinois garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
Before July arrives, get these ready
- 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.
Robinson, Illinois is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 23, giving you a growing season of approximately 192 days.
At an elevation of 555 feet, Crawford County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Leeks during the growing season.
Robinson Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7
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 Robinson
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.3–7.0) is within Leeks's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Crawford County is excellent for Leeks — 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
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Leeks Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | 3.5" | 3.1" | 0.4" | 💧 Light watering |
| May | 3.5" | 3.7" | 0" | ✅ Rainfall sufficient |
| Jun | 3.5" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 3.7" | 0" | ✅ Rainfall sufficient |
| Aug | 3.5" | 4" | 0" | ✅ Rainfall sufficient |
| Sep | 3.5" | 2.7" | 0.8" | 💧 Light watering |
| Oct | 3.5" | 2.5" | 1" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Crawford 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 — Robinson, IL
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 10 | Mar 10 – Mar 24 |
| Transplant Outdoors | April 14 | Apr 14 – Apr 28 |
| Direct Sow | March 31 | Mar 31 – Apr 21 |
| Harvest | July 14 | Jul 14 – Sep 29 |
| Fall Sowing | August 14 | Aug 14 – Aug 28 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | — |
| 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: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
192 days in Crawford County
Growing Tips for Leeks in Robinson
Direct sow Leeks outdoors after April 14 in Crawford 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 Robinson, IL?
In Robinson, IL, plant Leeks after the last frost (around April 14) and before the first frost (around October 23). Best results when soil holds above 50°F.
What growing zone is Robinson, IL for Leeks?
Robinson sits in USDA Zone 6b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.
Can Leeks grow in Robinson's climate?
Yes — Leeks grows well in Robinson's temperate climate. Robinson averages a 192-day frost-free season, with last frost around April 14 and first frost around October 23.
Your Crawford County Garden Planner — Free
A 22-page printable planner built for Crawford County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.