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When to plant Sweet Corn in Bath, IL

The best window to plant Sweet Corn in Bath, is April 22–May 13, when soil warms to 50°F. Last frost typically hits April 15; first frost October 14.

When to Plant Sweet Corn in Bath, IL

Mason County, Illinois Zone 6a August

August in Mason County, Illinois — your action list

August rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Mason County, Illinois.

Avg. last frost April 15
Avg. first frost October 14
Soil temp (4") 79°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs

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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.

Bath, Illinois is in USDA Zone 6a. The average last spring frost is April 15 and the first fall frost is October 14, giving you a growing season of approximately 182 days.

At an elevation of 768 feet, Mason County receives approximately 30.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Sweet Corn during the growing season.

Bath, IL (Zone 6a) Moderate season
182 days
Last Spring Frost April 15
182 growing days
First Fall Frost October 14

Bath Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Sweet Corn Planting Risk Windows

Early Start (70% safe) ✓ Fits season (73 days to spare)
Transplant: Apr 12 🍅 Harvest: Jun 14 – Jul 26
Recommended (50%) ✓ Fits season (77 days to spare)
Transplant: Apr 15 🍅 Harvest: Jun 17 – Jul 29
Safe Start (90%) ✓ Fits season (76 days to spare)
Transplant: Apr 30 🍅 Harvest: Jul 2 – Aug 13

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 Bath

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

Soil pH

Your soil pH (6.1–6.9) is within Sweet Corn's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — Sweet Corn will thrive.

How to Plant Sweet Corn

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

Succession Planting Sweet Corn

3
successive plantings in your 182-day season

Sow every 6.9 weeks. Last sowing by Jul 16 to harvest before frost.

Sweet 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 1,552 gal / 100 sq ft
Drought risk

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 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 6.5" 3" 3.5" 🚿 Regular watering
May 6.5" 3.3" 3.2" 💧 Light watering
Jun 6.5" 4.1" 2.4" 💧 Light watering
Jul 6.5" 3.3" 3.2" 💧 Light watering
Aug 6.5" 3.4" 3.1" 💧 Light watering
Sep 6.5" 2.7" 3.8" 🚿 Regular watering
Oct 6.5" 2.2" 4.3" 🚿 Regular watering
Nov 2" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Mason 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 needs ~1,088 GDD — county provides 2,639 GDD Excellent fit

Sweet Corn Planting Timeline — Bath, IL

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow April 22 Apr 22 – May 13
Harvest June 24 Jun 24 – Aug 5

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

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

182 days in Mason County

Growing Tips for Sweet Corn in Bath

Direct sow Sweet Corn outdoors after April 15 in Mason 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

  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

When should I plant Sweet Corn in Bath, IL?

In Bath, IL, plant Sweet Corn after the last frost (around April 15) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Bath, IL for Sweet Corn?

Bath 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 Bath's climate?

Yes — Sweet Corn grows well in Bath's temperate climate. Bath averages a 182-day frost-free season, with last frost around April 15 and first frost around October 14.

🌱

Your Mason County Garden Planner — Free

A 22-page printable planner built for Mason 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 Mason County, IL. Local conditions may vary. Last updated: August 2026.