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When to Plant Sweet Corn in Miller County, MO

Miller County, Missouri Zone 6b May

Your May game plan for Miller County, Missouri

We've pulled the most time-sensitive tasks for Miller County, Missouri this May and put them front and centre. Tackle them in order.

Avg. last frost April 6
Avg. first frost October 27
Soil temp (4") 65°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
Before June arrives, get these ready
  • First harvests: sweet corn

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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.

Miller County, Missouri is in USDA Zone 6b. The average last spring frost is April 6 and the first fall frost is October 27, giving you a growing season of approximately 204 days.

At an elevation of 1,086 feet, Miller County receives approximately 30.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Sweet Corn during the growing season.

Miller County, MO (Zone 6b) Long season
204 days
Last Spring Frost April 6
204 growing days
First Fall Frost October 27
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Miller County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (98 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 2 – Jul 14
Recommended (50%) ✓ Fits season (99 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 8 – Jul 20
Safe Start (90%) ✓ Fits season (99 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 23 – Aug 4

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 Miller County

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

Soil pH

Your soil pH (5.7–6.7) overlaps with Sweet Corn's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Miller 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 moderate (2.4%). Annual compost additions will help Sweet Corn.

How to Plant Sweet Corn

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

Succession Planting Sweet Corn

4
successive plantings in your 204-day season

Sow every 6.9 weeks. Last sowing by Jul 29 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 755 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 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 6.5" 3.4" 3.1" 💧 Light watering
May 6.5" 4.2" 2.3" 💧 Light watering
Jun 6.5" 3.6" 2.9" 💧 Light watering
Jul 6.5" 3.1" 3.4" 🚿 Regular watering
Aug 6.5" 3.1" 3.4" 🚿 Regular watering
Sep 6.5" 3.1" 3.4" 🚿 Regular watering
Oct 6.5" 2.4" 4.1" 🚿 Regular watering
Nov 1.8" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Miller 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 ~1,256 GDD — county provides 3,417 GDD Excellent fit

Sweet Corn Planting Timeline — Miller County, MO

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow April 13 Apr 13 – May 4
Harvest June 15 Jun 15 – Jul 27

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
September
October
November
December
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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: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

204 days in Miller County

Growing Tips for Sweet Corn in Miller County

Direct sow Sweet Corn outdoors after April 06 in Miller 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 Miller County, MO?

Miller County is in Zone 6b with an average last frost of April 6. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Miller County, MO?

Miller County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 6 and first fall frost is October 27.

🌱

Your Miller County Garden Planner — Free

A 24-page printable planner built for Miller 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.

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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 Miller County, MO. 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.