When should I plant Soybean in Zone 3b?

Direct sow Soybean outdoors around May 22. Harvest around Sep 9.

What is the last frost date for Zone 3b?

The average last spring frost date for Zone 3b is May 15. The first fall frost averages Sep 22, giving a 130-day growing season.

Can I grow Soybean in Zone 3b?

Yes. Soybean needs 110 days to harvest. Zone 3b has a 130-day growing season, which is sufficient.

Growing Soybean in Zone 3b

Zone 3b has harsh winters and a short growing season. Start Soybean early indoors to maximize your harvest window. Last frost: May 15. First frost: Sep 22.

Planting Calendar

Outdoor

Harvest

May 22Sep 22

Season: May 15 – Sep 22 (130 days)

Zone3b

Last FrostMay 15

First FrostSep 22

Season Length130 days

Days to Harvest110

SunFull Sun

Frost ToleranceNone

Spacing4/sqft (6" apart)

When to Plant Soybean in Zone 3b

Sow Seeds Outdoors: May 22

Direct sow Soybean seeds outdoors around May 22. Soil temperature should be at least 60°F. Space at 4/sqft (6" apart).

Harvest: Sep 9

First harvest approximately Sep 9 (~110 days from planting). Continue harvesting until first frost (Sep 22).

Companion Planting

✅ Corn ✅ Squash ✅ Sesame

❌ Onion❌ Garlic

Soybean in Other Zones

1a 1b 2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a 11b 12a 12b 13a 13b

Plan Your Soybean Garden

Track Soybean from seed to harvest with personalized frost dates, watering recommendations, and companion planting visualization.

Start Free Soybean Growing Guide