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When to Plant Corn in Roseau County, MN

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.

Roseau County, Minnesota is in USDA Zone 3a. The average last spring frost is May 21 and the first fall frost is September 22, giving you a growing season of approximately 124 days.

At an elevation of 655 feet, Roseau County receives approximately 32 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79ยฐF, so choose short-season varieties of Corn to ensure they mature before fall.

Roseau County, MN (Zone 3a) Short season
124 days
Last Spring Frost May 21
124 growing days
First Fall Frost September 22

Roseau County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (7 days to spare)
Transplant: May 11 🍅 Harvest: Jul 13 – Sep 7
Recommended (50%) ✓ Fits season (5 days to spare)
Transplant: May 21 🍅 Harvest: Jul 23 – Sep 17
Safe Start (90%) ✓ Fits season (7 days to spare)
Transplant: Jun 4 🍅 Harvest: Aug 6 – Oct 1

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 Roseau County

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

Soil pH

Your soil pH (5.9โ€“7.2) overlaps with Corn's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Roseau County is excellent for Corn โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) โ€” Corn will thrive.

How to Plant Corn

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

Succession Planting Corn

2
successive plantings in your 124-day season

Sow every 6.9 weeks. Last sowing by Jun 14 to harvest before frost.

Plant 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 551 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Corn

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 Corn Needs Rainfall You Supplement Action
Jan โ€” 1.2" 0" โ„๏ธ Dormant
Feb โ€” 1.6" 0" โ„๏ธ Dormant
Mar โ€” 1.8" 0" โ„๏ธ Dormant
Apr โ€” 2.9" 0" โ„๏ธ Dormant
May 6.5" 3.9" 2.6" ๐Ÿ’ง Light watering
Jun 6.5" 4.3" 2.2" ๐Ÿ’ง Light watering
Jul 6.5" 3.8" 2.7" ๐Ÿ’ง Light watering
Aug 6.5" 3.7" 2.8" ๐Ÿ’ง Light watering
Sep 6.5" 2.4" 4.1" ๐Ÿšฟ Regular watering
Oct โ€” 2.7" 0" โ„๏ธ Dormant
Nov โ€” 1.9" 0" โ„๏ธ Dormant
Dec โ€” 1.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Roseau County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

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" โ€” every day above 50ยฐF 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.

Corn needs ~740 GDD — county provides 1,147 GDD Excellent fit

Corn Planting Timeline โ€” Roseau County, MN

Corn Planting Calendar

Activity When Date Range
Direct Sow June 4 Jun 4 โ€“ Jun 25
Harvest August 6 Aug 6 โ€“ Oct 1

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.5"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

60โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 3a

๐Ÿ“† Growing Season

124 days in Roseau County

Growing Tips for Corn in Roseau County

Direct sow Corn outdoors after May 21 in Roseau County when soil has warmed and frost danger has passed.

Common pests for 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 rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Recommended Corn Varieties for Roseau County

Ultra-early corn varieties for your season

Earlivee (58d) Sugar Buns (72d) Early Sunglow (63d)

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 Roseau County, MN?

Roseau County is in Zone 3a with an average last frost of May 21. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Roseau County, MN?

Roseau County, Minnesota is in USDA Hardiness Zone 3a. The average last spring frost is May 21 and first fall frost is September 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Roseau County gardeners in Zone 3a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Roseau County, MN. Local conditions may vary. Last updated: April 2026.