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When to plant Corn in Saint Libory,

In Zone 7a (Saint Libory), direct-sow Corn between April 9 and April 30 for spring, after the April 2 last-frost mark.

When to Plant Corn in Saint Libory, IL

Corn
Saint Libory, IL Zone 7a June

Saint Libory, IL gardeners: here's your June plan

Each item below is timed to Saint Libory, IL's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 2
Avg. first frost November 2
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Harvest corn as they ripen

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

To set up a strong July, finish these tasks
  • First harvests: corn

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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.

Saint Libory, Illinois is in USDA Zone 7a. The average last spring frost is April 2 and the first fall frost is November 2, giving you a growing season of approximately 214 days.

At an elevation of 711 feet, St. Clair County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Corn during the growing season.

Saint Libory, IL (Zone 7a) Long season
214 days
Last Spring Frost April 2
214 growing days
First Fall Frost November 2

Saint Libory Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Corn Planting Risk Windows

Early Start (70% safe) ✓ Fits season (97 days to spare)
Transplant: Mar 26 🍅 Harvest: May 28 – Jul 23
Recommended (50%) ✓ Fits season (95 days to spare)
Transplant: Apr 2 🍅 Harvest: Jun 4 – Jul 30
Safe Start (90%) ✓ Fits season (101 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 Saint Libory

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

Soil pH

Your soil pH (6.0–7.3) overlaps with Corn's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in St. Clair County is excellent for Corn — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) — Corn will thrive.

How to Plant Corn

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

Succession Planting Corn

4
successive plantings in your 214-day season

Sow every 6.9 weeks. Last sowing by Jul 25 to harvest before frost.

Corn Water Budget

Plant needs
1.5″/week
Rainfall provides
0.7″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,899 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 6.5" 3.2" 3.3" 🚿 Regular watering
May 6.5" 3.8" 2.7" 💧 Light watering
Jun 6.5" 4" 2.5" 💧 Light watering
Jul 6.5" 3.8" 2.7" 💧 Light watering
Aug 6.5" 3.9" 2.6" 💧 Light watering
Sep 6.5" 3.3" 3.2" 💧 Light watering
Oct 6.5" 2.5" 4" 🚿 Regular watering
Nov 6.5" 2.4" 4.1" 🚿 Regular watering
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in St. Clair County). Supplement amounts are based on average rainfall — 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" — 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.

Corn needs ~1,340 GDD — county provides 3,584 GDD Excellent fit

Corn Planting Timeline — Saint Libory, IL

Corn Planting Calendar

Activity When Date Range
Direct Sow April 9 Apr 9 – Apr 30
Harvest June 11 Jun 11 – Aug 6

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

214 days in St. Clair County

Growing Tips for Corn in Saint Libory

Direct sow Corn outdoors after April 02 in St. Clair 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 →

When should I plant Corn in Saint Libory, ?

In Saint Libory, , plant Corn after the last frost (around April 2) and before the first frost (around November 2). Best results when soil holds above 50°F.

What growing zone is Saint Libory, for Corn?

Saint Libory sits in USDA Zone 7a. Corn grows reliably in zones 3a through 11b, so it's a good fit here.

Can Corn grow in Saint Libory's climate?

Yes — Corn grows well in Saint Libory's temperate climate. Saint Libory averages a 214-day frost-free season, with last frost around April 2 and first frost around November 2.

🌱

Your St. Clair County Garden Planner — Free

A 22-page printable planner built for St. Clair 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.

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