When to plant Sweet Corn in Vermilion County, IL
Plant Sweet Corn in Vermilion County, when soil hits 50°F — usually April 21. Continue planting through May 12 for the spring crop.
When to Plant Sweet Corn in Vermilion County, IL
July in Vermilion County, Illinois — your action list
A quick July briefing for Vermilion County, Illinois gardeners — what's urgent, what's next, and what can wait.
Sweet corn is bred for high sugar content in its kernels, which convert to starch rapidly after harvest. Modern supersweet varieties hold their sweetness longer.
Vermilion County, 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 Sweet Corn during the growing season.
Vermilion County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-6.9
Drainage
Well Drained
Sweet Corn Planting Risk Windows
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 Vermilion County
How your county's soil matches Sweet Corn's growing requirements.
Soil pH
Your soil pH (6.2–6.9) is within Sweet Corn's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Vermilion County is excellent for Sweet Corn — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.2%) — Sweet Corn will thrive.
How to Plant Sweet Corn
Succession Planting Sweet Corn
Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.
Sweet Corn Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Sweet Corn
Sweet 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 | Sweet 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.
Sweet 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.
Sweet Corn Planting Timeline — Vermilion County, IL
Sweet Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 21 | Apr 21 – May 12 |
| Harvest | June 23 | Jun 23 – Aug 4 |
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
1.5"/week · 2-3 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: ideal
🗺️ USDA Zone
Zone 6a
📆 Growing Season
185 days in Vermilion County
Growing Tips for Sweet Corn in Vermilion County
Direct sow Sweet Corn outdoors after April 14 in Vermilion County when soil has warmed and frost danger has passed.
Common pests for Sweet 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 for wind pollination. Direct sow after soil is warm. Isolate supersweet varieties from other corn types to prevent cross-pollination.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Sweet Corn in Other Locations
Frequently Asked Questions
When should I plant Sweet Corn in Vermilion County, IL?
Vermilion County is in Zone 6a with an average last frost of April 14. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Vermilion County, IL?
Vermilion County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 16.
When should I plant Sweet Corn in Vermilion County, IL?
In Vermilion County, IL, plant Sweet 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 Vermilion County, IL for Sweet Corn?
Vermilion County sits in USDA Zone 6a. Sweet Corn grows reliably in zones 3a through 11b, so it's a good fit here.
Can Sweet Corn grow in Vermilion County's climate?
Yes — Sweet Corn grows well in Vermilion County's temperate climate. Vermilion County 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.