Soybeans should be planted during the spring, two to three weeks after the last frost in colder climates, and in warmer climates, when the soil temperature reaches about 60 degrees Fahrenheit. Soybeans are not frost tolerant and grow best when air temperatures 60 to 70 degrees Fahrenheit.
The actual time of year to plant soybeans varies by region. Soybeans planted in the spring typically mature in the autumn. Planting soybeans in a spot with full sun will give the maximum yield. Soybeans grow in partial sun, but the plants do not produce as heavily. The beans should be harvested when they are plump and green but before they begin to yellow on the plant.