When to plant Corn in O Fallon, MO
For O Fallon, gardeners: plant Corn April 20 through May 11 once soil reads 50°F.
When to Plant Corn in O Fallon, MO
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.
O Fallon, Missouri is in USDA Zone 6b. The average last spring frost is April 13 and the first fall frost is October 24, giving you a growing season of approximately 194 days.
At an elevation of 1,295 feet, St. Charles County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Corn during the growing season.
O Fallon Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.6
Drainage
Well Drained
How Much Corn to Grow
For a family of 4, plant approximately 60 corn plants in about 120 sq ft. In St. Charles County's 194-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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3" | 1.3" | 💧 Light watering |
| May | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jun | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Aug | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Sep | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Oct | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Nov | — | 2.1" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in St. Charles County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Corn Planting Timeline — O Fallon, MO
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 20 | Apr 20 – May 11 |
| Harvest | June 22 | Jun 22 – Aug 17 |
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 6b
📆 Growing Season
194 days in St. Charles County
Growing Tips for O Fallon
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 O Fallon, MO?
In O Fallon, MO, plant Corn after the last frost (around April 13) and before the first frost (around October 24). Best results when soil holds above 50°F.
What growing zone is O Fallon, MO for Corn?
O Fallon sits in USDA Zone 6b. Corn grows reliably in zones 3a through 11b, so it's a good fit here.
Can Corn grow in O Fallon's climate?
Yes — Corn grows well in O Fallon's temperate climate. O Fallon averages a 194-day frost-free season, with last frost around April 13 and first frost around October 24.
Your St. Charles County Garden Planner — Free
A 22-page printable planner built for St. Charles 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.