The soya bean, or soybean, is an annual legume that grows in bushes about one to three feet tall and produces green pods one to four inches long. Soybeans require warmer weather than other bean plants, and do not grow well in shady areas or in daytime temperatures under 70°F. They also take longer to mature: one to two months for fresh beans and three to five months for dry beans, depending on the temperature and other factors. Soybeans are a nutritious food that provides fiber, protein and calcium.
Add peat moss, mulch or sand to clay-based soil to aerate it and prevent moisture loss.
Soybeans require warm weather, sun and loose, aerated, slightly acidic soil to grow well. If your soil is clay-based, it can form a hard crust, which prevents soybeans from sprouting.
Plant soybeans in the spring, when the soil temperature is at least 60°F. Soybeans can survive in cold temperatures and half-shaded areas, but the yield is reduced. Cover soybean plants if the nighttime temperatures drop to 40° or below.
Plant the soybean seeds two to four inches apart, in rows about two feet apart. Seeds should be planted one to one and a half inches deep in moist soil, and up to two inches deep in dry soil. Never plant the seeds more than two and a half inches deep.
After the seeds sprout, thin the plants so they are four to six inches apart. Water regularly and add mulch, compost and/or fertilizer to the growing plants. Soybeans have a symbiotic relationship with nitrogen-fixing bacteria in the soil, but if they have not been grown in this particular soil for several years, you may need to add nitrogen-rich fertilizer or treat the seeds with nitrogen-fixing bacteria prior to planting.
For fresh soybeans (edamame), harvest the pods when they are still green, one to two months after planting. For dry beans, harvest them when the pods are more mature, 100 days or more after planting.