When to Plant Soybeans in USDA Zone 3b
April in Zone 3b — your action list
Each item below is timed to Zone 3b's frost dates and soil temperatures. Skip nothing, stress about nothing.
Coming up in May — start thinking about
- Direct-sowing: soybeans
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.
In Zone 3b, the average last spring frost is around May 10 and the first fall frost is around September 22, giving you a growing season of approximately 135 days.
Soybeans Planting Timeline — Zone 3b
Where Is USDA Zone 3b?
The map below highlights the states that contain Zone 3b. Click any state to see the Soybeans planting schedule for that location.
Soybeans Planting Calendar — Zone 3b
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 24 | May 24 – Jun 14 |
| Harvest | August 16 | Aug 16 – Sep 27 |
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 | — |
| November | — |
| December | — |
Free Zone 3b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 3b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
Days to Maturity
80–120 days
Soil pH
6 – 7
Zone Temperature Range
°F to °F average annual minimum
Growing Season
135 days (Zone average)
Planting Specifications
| Planting Depth | 1 inches |
| Plant Spacing | 15 inches apart |
| Row Spacing | 24 inches between rows |
Growing Tips for Soybeans in Zone
Zone has a short growing season (~135 days). Start Soybeans indoors early and use season-extension techniques like row covers and cold frames.
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
The Gardener's Encyclopedia to Companion Planting
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Saving Soybeans Seeds
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Soybeans in Other Zones
Soybeans by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Soybeans in Zone 3b?
In Zone 3b, plan your Soybeans planting around the average last frost date of May 10. Direct sow outdoors around May 24.
Can Soybeans grow in Zone 3b?
Yes, Soybeans can grow well in Zone 3b, hardy in USDA zones 3a through 10b. Zone 3b has a growing season of approximately 135 days, which is sufficient for Soybeans (80-120 days to maturity).
When can I harvest Soybeans in Zone 3b?
In Zone 3b, expect to harvest Soybeans from August 16 – September 27. Soybeans takes 80-120 days from planting to harvest.
What is the last frost date for Zone 3b?
The average last spring frost in Zone 3b is around May 10, and the first fall frost is around September 22. This gives a growing season of approximately 135 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Soybeans?
Good companion plants for Soybeans include Corn, Squash Summer, Potatoes. These companions can help with pest control, pollination, and nutrient sharing.
Your Free Printable Garden Planner
A 24-page printable planner tailored to your zone. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.