Blog

When to plant Corn in Sidell,

For Sidell, gardeners: plant Corn April 21 through May 12 once soil reads 50°F.

When to Plant Corn in Sidell, IL

Corn
Sidell, IL Zone 6a June

Sidell, IL gardeners: here's your June plan

We've pulled the most time-sensitive tasks for Sidell, IL this June and put them front and centre. Tackle them in order.

Avg. last frost April 14
Avg. first frost October 16
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 14.8 hrs
  1. Harvest corn as they ripen

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

July will be here before you know it — start on
  • First harvests: corn

Instant PDF download. No spam, unsubscribe any time.

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.

Sidell, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 16, giving you a growing season of approximately 185 days.

At an elevation of 1,218 feet, Vermilion County receives approximately 31.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Corn during the growing season.

Sidell, IL (Zone 6a) Moderate season
185 days
Last Spring Frost April 14
185 growing days
First Fall Frost October 16

Sidell Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Corn Planting Risk Windows

Early Start (70% safe) ✓ Fits season (64 days to spare)
Transplant: Apr 11 🍅 Harvest: Jun 13 – Aug 8
Recommended (50%) ✓ Fits season (66 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 16 – Aug 11
Safe Start (90%) ✓ Fits season (61 days to spare)
Transplant: May 3 🍅 Harvest: Jul 5 – Aug 30

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 Sidell

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

Soil pH

Your soil pH (6.2–6.9) is within Corn's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) — Corn will thrive.

How to Plant Corn

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

Succession Planting Corn

3
successive plantings in your 185-day season

Sow every 6.9 weeks. Last sowing by Jul 08 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 1,564 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 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 6.5" 3.1" 3.4" 🚿 Regular watering
May 6.5" 3.9" 2.6" 💧 Light watering
Jun 6.5" 3.7" 2.8" 💧 Light watering
Jul 6.5" 3.8" 2.7" 💧 Light watering
Aug 6.5" 3.5" 3" 💧 Light watering
Sep 6.5" 2.5" 4" 🚿 Regular watering
Oct 6.5" 2.1" 4.4" 🚿 Regular watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Vermilion 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 ~1,100 GDD — county provides 2,543 GDD Excellent fit

Corn Planting Timeline — Sidell, 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: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

185 days in Vermilion County

Growing Tips for Corn in Sidell

Direct sow Corn outdoors after April 14 in Vermilion 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 Sidell, ?

In Sidell, , plant Corn after the last frost (around April 14) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Sidell, for Corn?

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

Can Corn grow in Sidell's climate?

Yes — Corn grows well in Sidell's temperate climate. Sidell averages a 185-day frost-free season, with last frost around April 14 and first frost around October 16.

🌱

Your Vermilion County Garden Planner — Free

A 22-page printable planner built for Vermilion 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.

Instant PDF download. No spam, unsubscribe any time.

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