When to plant Soybeans in Polk County, MN
In Polk County, Soybeans is a spring-only crop. Plant May 25–June 15 once soil hits 50°F.
When to Plant Soybeans in Polk County, MN
Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.
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 Soybeans to ensure they mature before fall.
Polk County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.2
Drainage
Well Drained
Monthly Watering Guide for Soybeans
Soybeans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Soybeans 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 | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jun | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Sep | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light 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.
Soybeans Planting Timeline — Polk County, MN
Soybeans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 25 | May 25 – Jun 15 |
| Harvest | August 17 | Aug 17 – Oct 12 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow |
| June | Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 4a
📆 Growing Season
143 days in Polk County
Growing Tips for Polk County
Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Soybeans in Other Locations
Frequently Asked Questions
When should I plant Soybeans in Polk County, MN?
Polk County is in Zone 4a with an average last frost of May 11. Plan your Soybeans 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.
When should I plant Soybeans in Polk County, MN?
In Polk County, MN, plant Soybeans after the last frost (around May 11) and before the first frost (around October 1). Best results when soil holds above 50°F.
What growing zone is Polk County, MN for Soybeans?
Polk County sits in USDA Zone 4a. Soybeans grows reliably in zones 3a through 10b, so it's a good fit here.
Can Soybeans grow in Polk County's climate?
Yes — Soybeans grows well in Polk County's temperate climate. Polk County averages a 143-day frost-free season, with last frost around May 11 and first frost around October 1.
Your Polk County Garden Planner — Free
A 22-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.