When to Plant Soybeans in Polk County, OR
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, Oregon is in USDA Zone 8b. The average last spring frost is April 10 and the first fall frost is October 31, giving you a growing season of approximately 204 days.
At an elevation of 331 feet, Polk County receives approximately 54.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Soybeans to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Soybeans root diseases.
Polk County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Soybeans Planting Timeline — Polk County, OR
Soybeans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 17 | Apr 17 – May 8 |
| Harvest | July 10 | Jul 10 – Sep 4 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| 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 8b
📆 Growing Season
204 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, OR?
Polk County is in Zone 8b with an average last frost of April 10. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.
What planting zone is Polk County, OR?
Polk County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 10 and first fall frost is October 31.
Your Polk County Garden Planner — Free
A 22-page printable planner built for Polk County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.