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When to Plant Sweet Corn in Ozaukee County, WI

Ozaukee County, Wisconsin Zone 5b May

Your May gardening checklist

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

Avg. last frost April 27
Avg. first frost October 11
Soil temp (4") 56°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs
  1. Put sweet corn seeds straight in the ground

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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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.

Ozaukee County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 11, giving you a growing season of approximately 167 days.

At an elevation of 1,277 feet, Ozaukee County receives approximately 32.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Sweet Corn to ensure they mature before fall.

Ozaukee County, WI (Zone 5b) Moderate season
167 days
Last Spring Frost April 27
167 growing days
First Fall Frost October 11
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Ozaukee County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (60 days to spare)
Transplant: Apr 24 🍅 Harvest: Jun 26 – Aug 7
Recommended (50%) ✓ Fits season (62 days to spare)
Transplant: Apr 27 🍅 Harvest: Jun 29 – Aug 10
Safe Start (90%) ✓ Fits season (61 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Aug 26

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 Ozaukee County

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

Soil pH

Your soil pH (6.1–7.1) overlaps with Sweet Corn's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Sweet Corn.

Organic Matter

Organic matter is excellent (4.7%) — 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 167-day season

Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,683 gal / 100 sq ft

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 2.2" 0" ❄️ Dormant
Apr 6.5" 2.7" 3.8" 🚿 Regular watering
May 6.5" 3.3" 3.2" 💧 Light watering
Jun 6.5" 3.9" 2.6" 💧 Light watering
Jul 6.5" 4" 2.5" 💧 Light watering
Aug 6.5" 3.8" 2.7" 💧 Light watering
Sep 6.5" 2.9" 3.6" 🚿 Regular watering
Oct 6.5" 2.5" 4" 🚿 Regular watering
Nov 2.3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ozaukee 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 ~975 GDD — county provides 2,171 GDD Excellent fit

Sweet Corn Planting Timeline — Ozaukee County, WI

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow May 4 May 4 – May 25
Harvest July 6 Jul 6 – Aug 17

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June
July Harvest
August Harvest
September
October
November
December
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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 5b

📆 Growing Season

167 days in Ozaukee County

Growing Tips for Sweet Corn in Ozaukee County

Direct sow Sweet Corn outdoors after April 27 in Ozaukee 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 →

Frequently Asked Questions

When should I plant Sweet Corn in Ozaukee County, WI?

Ozaukee County is in Zone 5b with an average last frost of April 27. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ozaukee County, WI?

Ozaukee County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 11.

🌱

Your Ozaukee County Garden Planner — Free

A 24-page printable planner built for Ozaukee County (Zone 5b). 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 Ozaukee County, WI. Local conditions may vary. Last updated: May 2026.

Sources & credits

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