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When to plant Sweet Corn in Delta County, MI

Delta County's spring Sweet Corn window runs May 19 through June 9. time plantings around the expected last-frost window for best survival.

When to Plant Sweet Corn in Delta County, MI

Delta County, Michigan Zone 5a June

Your June planting checklist for Delta County, Michigan

Your Delta County, Michigan garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost May 12
Avg. first frost October 14
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15.5 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.

Delta County, Michigan is in USDA Zone 5a. The average last spring frost is May 12 and the first fall frost is October 14, giving you a growing season of approximately 155 days.

At an elevation of 921 feet, Delta County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Sweet Corn to ensure they mature before fall.

Delta County, MI (Zone 5a) Moderate season
155 days
Last Spring Frost May 12
155 growing days
First Fall Frost October 14

Delta County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Sweet Corn Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Transplant: May 6 🍅 Harvest: Jul 8 – Aug 19
Recommended (50%) ✓ Fits season (50 days to spare)
Transplant: May 12 🍅 Harvest: Jul 14 – Aug 25
Safe Start (90%) ✓ Fits season (54 days to spare)
Transplant: May 26 🍅 Harvest: Jul 28 – Sep 8

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 Delta County

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

Soil pH

Your soil pH (6.2–6.8) is within Sweet Corn's preferred range (6.0–7.0).

Soil Texture

The silt loam soil in Delta 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

2
successive plantings in your 155-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
1.1″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 640 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 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 6.5" 5.3" 1.2" 💧 Light watering
Jun 6.5" 4.8" 1.7" 💧 Light watering
Jul 6.5" 4.8" 1.7" 💧 Light watering
Aug 6.5" 3.8" 2.7" 💧 Light watering
Sep 6.5" 3.6" 2.9" 💧 Light watering
Oct 6.5" 3.3" 3.2" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Delta 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 ~919 GDD — county provides 1,898 GDD Excellent fit

Sweet Corn Planting Timeline — Delta County, MI

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow May 19 May 19 – Jun 9
Harvest July 21 Jul 21 – Sep 1

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

155 days in Delta County

Growing Tips for Sweet Corn in Delta County

Direct sow Sweet Corn outdoors after May 12 in Delta 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 Delta County, MI?

Delta County is in Zone 5a with an average last frost of May 12. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Delta County, MI?

Delta County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 12 and first fall frost is October 14.

When should I plant Sweet Corn in Delta County, MI?

In Delta County, MI, plant Sweet Corn after the last frost (around May 12) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Delta County, MI for Sweet Corn?

Delta County sits in USDA Zone 5a. Sweet Corn grows reliably in zones 3a through 11b, so it's a good fit here.

Can Sweet Corn grow in Delta County's climate?

Yes — Sweet Corn grows well in Delta County's temperate climate. Delta County averages a 155-day frost-free season, with last frost around May 12 and first frost around October 14.

🌱

Your Delta County Garden Planner — Free

A 22-page printable planner built for Delta County (Zone 5a). 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 Delta County, MI. Local conditions may vary. Last updated: June 2026.

Sources & credits

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