When to plant Corn in Herrin, IL
Plant Corn in Herrin from April 17 to May 8 in spring. Herrin sits in USDA Zone 7a, with last frost around April 10 and first frost on October 20.
When to Plant Corn in Herrin, IL
Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.
Herrin, Illinois is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 20, giving you a growing season of approximately 193 days.
At an elevation of 1,253 feet, Williamson County receives approximately 38.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Corn during the growing season.
Herrin Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7.2
Drainage
Well Drained
How Much Corn to Grow
For a family of 4, plant approximately 60 corn plants in about 120 sq ft. In Williamson County's 193-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Monthly Watering Guide for Corn
Corn needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Corn Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 4" | 0.3" | 💧 Light watering |
| May | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Williamson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Corn Planting Timeline — Herrin, IL
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 17 | Apr 17 – May 8 |
| Harvest | June 19 | Jun 19 – Aug 14 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
60–100 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 7a
📆 Growing Season
193 days in Williamson County
Growing Tips for Herrin
Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Corn in Other Locations
When should I plant Corn in Herrin, IL?
In Herrin, IL, plant Corn after the last frost (around April 10) and before the first frost (around October 20). Best results when soil holds above 50°F.
What growing zone is Herrin, IL for Corn?
Herrin sits in USDA Zone 7a. Corn grows reliably in zones 3a through 11b, so it's a good fit here.
Can Corn grow in Herrin's climate?
Yes — Corn grows well in Herrin's temperate climate. Herrin averages a 193-day frost-free season, with last frost around April 10 and first frost around October 20.
Your Williamson County Garden Planner — Free
A 22-page printable planner built for Williamson County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.