When to Plant Corn in Polk County, MN
Your May planting checklist for Polk County, Minnesota
Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.
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Outdoor sowing time: corn
Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.
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.
Polk County, Minnesota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is October 1, giving you a growing season of approximately 143 days.
At an elevation of 1,053 feet, Polk County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Corn to ensure they mature before fall.
Polk County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.2
Drainage
Well Drained
Plant Planting Risk Windows
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 Polk County
How your county's soil matches Corn's growing requirements.
Soil pH
Your soil pH (5.9–7.2) overlaps with Corn's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Polk County is excellent for Corn — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.2%) — Corn will thrive.
How to Plant Corn
Succession Planting Corn
Sow every 6.9 weeks. Last sowing by Jun 23 to harvest before frost.
Plant Water Budget
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | — | 3.6" | 0" | ❄️ Dormant |
| May | 6.5" | 3.6" | 2.9" | 💧 Light watering |
| Jun | 6.5" | 4.8" | 1.7" | 💧 Light watering |
| Jul | 6.5" | 4.5" | 2" | 💧 Light watering |
| Aug | 6.5" | 3.4" | 3.1" | 💧 Light watering |
| Sep | 6.5" | 2.9" | 3.6" | 🚿 Regular watering |
| Oct | 6.5" | 2.9" | 3.6" | 🚿 Regular watering |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Polk County). Supplement amounts are based on average rainfall — 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" — 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.
Corn Planting Timeline — Polk County, MN
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 25 | May 25 – Jun 15 |
| Harvest | July 27 | Jul 27 – Sep 21 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
60–100 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 4a
📆 Growing Season
143 days in Polk County
Growing Tips for Corn in Polk County
Direct sow Corn outdoors after May 11 in Polk 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.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Corn in Other Locations
Frequently Asked Questions
When should I plant Corn in Polk County, MN?
Polk County is in Zone 4a with an average last frost of May 11. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Polk County, MN?
Polk County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is October 1.
Your Polk County Garden Planner — Free
A 24-page printable planner built for Polk 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.