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When to Plant Corn in Gallatin County, 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.

Gallatin County, Illinois is in USDA Zone 6b. The average last spring frost is April 6 and the first fall frost is October 30, giving you a growing season of approximately 207 days.

At an elevation of 1,391 feet, Gallatin County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Corn during the growing season.

Gallatin County, IL (Zone 6b) Long season
207 days
Last Spring Frost April 6
207 growing days
First Fall Frost October 30

Gallatin County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (86 days to spare)
Transplant: Mar 30 🍅 Harvest: Jun 1 – Jul 27
Recommended (50%) ✓ Fits season (88 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 8 – Aug 3
Safe Start (90%) ✓ Fits season (96 days to spare)
Transplant: Apr 17 🍅 Harvest: Jun 19 – Aug 14

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 Gallatin County

How your county's soil matches Corn's growing requirements.

Soil pH

Your soil pH (6.3โ€“6.8) is within Corn's preferred range (6.0โ€“7.0).

Soil Texture

The silt loam soil in Gallatin County is excellent for Corn โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.4%) โ€” Corn will thrive.

How to Plant Corn

1"
Planting Depth
12"
Between Plants
36"
Between Rows

Succession Planting Corn

4
successive plantings in your 207-day season

Sow every 6.9 weeks. Last sowing by Jul 22 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,656 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Corn

Corn needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Corn Needs Rainfall You Supplement Action
Jan โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.6" 0" โ„๏ธ Dormant
Mar โ€” 2.7" 0" โ„๏ธ Dormant
Apr 6.5" 3.3" 3.2" ๐Ÿ’ง Light watering
May 6.5" 4.2" 2.3" ๐Ÿ’ง Light watering
Jun 6.5" 4.4" 2.1" ๐Ÿ’ง Light watering
Jul 6.5" 4.5" 2" ๐Ÿ’ง Light watering
Aug 6.5" 3.7" 2.8" ๐Ÿ’ง Light watering
Sep 6.5" 3.3" 3.2" ๐Ÿ’ง Light watering
Oct 6.5" 2.7" 3.8" ๐Ÿšฟ Regular watering
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 2.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Gallatin County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Corn 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" โ€” every day above 50ยฐF 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.

Corn needs ~1,100 GDD — county provides 2,846 GDD Excellent fit

Corn Planting Timeline โ€” Gallatin County, IL

Corn Planting Calendar

Activity When Date Range
Direct Sow April 13 Apr 13 โ€“ May 4
Harvest June 15 Jun 15 โ€“ Aug 10

Plant 1" deep ยท 12" apart ยท Rows 36" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Direct Sow
May Direct Sow
June Harvest
July Harvest
August Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.5"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

60โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

207 days in Gallatin County

Growing Tips for Corn in Gallatin County

Direct sow Corn outdoors after April 06 in Gallatin County when soil has warmed and frost danger has passed.

Common pests for Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.

General growing tips

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

  • Tomatoes
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Gallatin County, IL?

Gallatin County is in Zone 6b with an average last frost of April 6. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Gallatin County, IL?

Gallatin County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 6 and first fall frost is October 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Gallatin County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Gallatin County, IL. Local conditions may vary. Last updated: April 2026.