Unlike other beans, which grow on both bushes and climbing vines, all edamame beans are low-growing bush beans. Popular varieties include Black Pearl, Sayamusume and Midori Giant.
Edamame do best in full-sun locations with well-drained soil that has plenty of organic matter. Raised-bed gardens make great sites. The bean plants grow best in a slightly acidic soil with a pH range of about 6.0 to 6.5. Work organic matter into the garden bed to improve the soil's texture and fertilize with 05-10-10 fertilizer.
After the beans sprout spread mulch around their base, being careful not to let the mulch touch the stems of the plants. Bean plants need about 1" of water per week. Pull any weeds that sprout by hand, but never work around bean plants when they're wet as this can spread disease. Pests are not a major problem with edamame, but keep an eye out for aphids and leaf beetles.
All the beans on a single edamame plant mature at the same time. When the beans are almost touching one another inside the pod, and the raw beans taste mild and sweet, the edamame is ready to harvest. The easiest way to harvest them is to pull the entire plant then pick off the pods.