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When to plant Corn in Scott County, IL

Scott County gardeners should plant Corn between April 21 and May 12 in spring. With Scott County's Zone 6a climate (last frost April 14), Corn needs 60–100 days to mature — plant by July 9 for a full harvest.

When to Plant Corn in Scott County, IL

Corn
Scott County, Illinois Zone 6a June

Top priorities for Scott County, Illinois gardeners in June

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 14
Avg. first frost October 17
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. Bring in the corn

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

July prep starts now
  • 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.

Scott County, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 987 feet, Scott County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Corn to ensure they mature before fall.

Scott County, IL (Zone 6a) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17

Scott County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.1

Drainage

Well Drained

Corn Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Transplant: Apr 9 🍅 Harvest: Jun 11 – Aug 6
Recommended (50%) ✓ Fits season (67 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 16 – Aug 11
Safe Start (90%) ✓ Fits season (61 days to spare)
Transplant: May 1 🍅 Harvest: Jul 3 – Aug 28

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 Scott County

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

Soil pH

Your soil pH (6.0–7.1) overlaps with Corn's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Corn.

Organic Matter

Organic matter is excellent (4.4%) — Corn will thrive.

How to Plant Corn

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

Succession Planting Corn

3
successive plantings in your 186-day season

Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.

Corn Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,826 gal / 100 sq ft

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 2.8" 0" ❄️ Dormant
Apr 6.5" 3" 3.5" 🚿 Regular watering
May 6.5" 4.4" 2.1" 💧 Light watering
Jun 6.5" 5.2" 1.3" 💧 Light watering
Jul 6.5" 4.2" 2.3" 💧 Light watering
Aug 6.5" 4.2" 2.3" 💧 Light watering
Sep 6.5" 3.2" 3.3" 🚿 Regular watering
Oct 6.5" 2.8" 3.7" 🚿 Regular watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Scott 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 ~1,040 GDD — county provides 2,418 GDD Excellent fit

Corn Planting Timeline — Scott County, IL

Corn Planting Calendar

Activity When Date Range
Direct Sow April 21 Apr 21 – May 12
Harvest June 23 Jun 23 – Aug 18

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

Month-by-Month Timeline

MonthActivities
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

1.5"/week · 2-3 times/week

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

186 days in Scott County

Growing Tips for Corn in Scott County

Direct sow Corn outdoors after April 14 in Scott 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 Scott County, IL?

Scott County is in Zone 6a with an average last frost of April 14. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Scott County, IL?

Scott County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 17.

When should I plant Corn in Scott County, IL?

In Scott County, IL, plant Corn after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Scott County, IL for Corn?

Scott County sits in USDA Zone 6a. Corn grows reliably in zones 3a through 11b, so it's a good fit here.

Can Corn grow in Scott County's climate?

Yes — Corn grows well in Scott County's temperate climate. Scott County averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.

🌱

Your Scott County Garden Planner — Free

A 22-page printable planner built for Scott County (Zone 6a). 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 Scott County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.