When to plant Soybeans in St. Clair County, MO
In Zone 6b (St. Clair County), direct-sow Soybeans between April 15 and May 6 for spring, after the April 8 last-frost mark.
When to Plant Soybeans in St. Clair County, MO
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.
St. Clair County, Missouri is in USDA Zone 6b. The average last spring frost is April 8 and the first fall frost is October 26, giving you a growing season of approximately 201 days.
At an elevation of 699 feet, St. Clair County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Soybeans during the growing season.
St. Clair County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Soybeans Planting Timeline — St. Clair County, MO
Soybeans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 15 | Apr 15 – May 6 |
| Harvest | July 8 | Jul 8 – Sep 2 |
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 6b
📆 Growing Season
201 days in St. Clair County
Growing Tips for St. Clair 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 St. Clair County, MO?
St. Clair County is in Zone 6b with an average last frost of April 8. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Clair County, MO?
St. Clair County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 8 and first fall frost is October 26.
When should I plant Soybeans in St. Clair County, MO?
In St. Clair County, MO, plant Soybeans after the last frost (around April 8) and before the first frost (around October 26). Best results when soil holds above 50°F.
What growing zone is St. Clair County, MO for Soybeans?
St. Clair County sits in USDA Zone 6b. Soybeans grows reliably in zones 3a through 10b, so it's a good fit here.
Can Soybeans grow in St. Clair County's climate?
Yes — Soybeans grows well in St. Clair County's temperate climate. St. Clair County averages a 201-day frost-free season, with last frost around April 8 and first frost around October 26.
Your St. Clair County Garden Planner — Free
A 22-page printable planner built for St. Clair County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.