When to plant Sweet Corn in Sumner, IL
Sumner gardeners should plant Sweet Corn between April 20 and May 11 in spring. With Sumner's Zone 6b climate (last frost April 13), Sweet Corn needs 60–90 days to mature — plant by July 29 for a full harvest.
When to Plant Sweet Corn in Sumner, IL
June to-do list for Lawrence County, Illinois
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.
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.
Sumner, Illinois is in USDA Zone 6b. The average last spring frost is April 13 and the first fall frost is October 27, giving you a growing season of approximately 197 days.
At an elevation of 969 feet, Lawrence County receives approximately 35.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Sweet Corn during the growing season.
Sumner Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-7.3
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 Sumner
How your county's soil matches Sweet Corn's growing requirements.
Soil pH
Your soil pH (5.8–7.3) overlaps with Sweet Corn's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Lawrence County is excellent for Sweet Corn — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Sweet Corn.
How to Plant Sweet Corn
Succession Planting Sweet Corn
Sow every 6.9 weeks. Last sowing by Jul 29 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 | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | 6.5" | 3.3" | 3.2" | 💧 Light watering |
| May | 6.5" | 4" | 2.5" | 💧 Light watering |
| Jun | 6.5" | 4.5" | 2" | 💧 Light watering |
| Jul | 6.5" | 3.9" | 2.6" | 💧 Light watering |
| Aug | 6.5" | 3.9" | 2.6" | 💧 Light watering |
| Sep | 6.5" | 3.2" | 3.3" | 🚿 Regular watering |
| Oct | 6.5" | 2.6" | 3.9" | 🚿 Regular watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Lawrence 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 — Sumner, IL
Sweet Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 20 | Apr 20 – May 11 |
| Harvest | June 22 | Jun 22 – Aug 3 |
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: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
197 days in Lawrence County
Growing Tips for Sweet Corn in Sumner
Direct sow Sweet Corn outdoors after April 13 in Lawrence 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
When should I plant Sweet Corn in Sumner, IL?
In Sumner, IL, plant Sweet Corn after the last frost (around April 13) and before the first frost (around October 27). Best results when soil holds above 50°F.
What growing zone is Sumner, IL for Sweet Corn?
Sumner sits in USDA Zone 6b. Sweet Corn grows reliably in zones 3a through 11b, so it's a good fit here.
Can Sweet Corn grow in Sumner's climate?
Yes — Sweet Corn grows well in Sumner's temperate climate. Sumner averages a 197-day frost-free season, with last frost around April 13 and first frost around October 27.
Your Lawrence County Garden Planner — Free
A 22-page printable planner built for Lawrence County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.