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When to Plant Corn in Marshall County, SD

Corn

Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.

Marshall County, South Dakota is in USDA Zone 4a. The average last spring frost is May 8 and the first fall frost is October 4, giving you a growing season of approximately 149 days.

At an elevation of 817 feet, Marshall County receives approximately 31.2 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Corn to ensure they mature before fall.

Marshall County, SD (Zone 4a) Short season
149 days
Last Spring Frost May 8
149 growing days
First Fall Frost October 4

Marshall County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

How Much Corn to Grow

1-2 ears
Average yield per plant
15
Plants per person
30 sq ft
Space per person

For a family of 4, plant approximately 60 corn plants in about 120 sq ft. In Marshall County's 149-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Corn Planting Timeline — Marshall County, SD

Corn Planting Calendar

Activity When Date Range
Direct Sow May 22 May 22 – Jun 12
Harvest July 24 Jul 24 – Sep 18

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

Moderate — regular watering

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 4a

📆 Growing Season

149 days in Marshall County

Growing Tips for Marshall County

Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Marshall County, SD?

Marshall County is in Zone 4a with an average last frost of May 8. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marshall County, SD?

Marshall County, South Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 8 and first fall frost is October 4.

🌱

Your Marshall County Garden Planner — Free

A 22-page printable planner built for Marshall County (Zone 4a). 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 Marshall County, SD. 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.