A green bean can refer to most types of bean plants that are harvested as green pods before reaching full maturity. In America, the common green bean or string green bean is a popular garden vegetable. The green bean life cycle takes approximately one year, during which time the seed passes through several growing stages.
Germination is the first stage of the green bean's life cycle, and is the process in which the seed begins to form a sprout or seedling. With the proper watering, a green bean's germination may occur within a few days to a week of planting the seed, which is when the seed initially develops roots.
After approximately one week, when the seedling begins to poke through the soil, phototropism begins to work on the plant. During phototropism, the seedling will make orienting movement toward the sunlight, growing from the seed upward through the earth's soil and vertically toward the source of sunlight. The growth stage of the green bean takes approximately six weeks, depending on the amount of sunlight.
The reproduction, or flowering, stage of the green bean begins after the bean sprout has straightened fully outside of the soil. At this stage, the sprout has not only come through the soil, but it is firmly pointing upright toward the sunlight. This usually takes place between 6 and 8 weeks after planting. Flowers begin forming on the sprout at that time, and fertilization begins. Fertilization will wither the bean sprout's flowers so that the flower's ovaries can begin to grow into pods.
Immature Green Bean
Once the bean pods form, the life cycle of the green bean begins its maturity stages. It is possible to harvest bean pods when they first form a green color. Pods can ripen for several weeks, forming larger pods. The common American green bean is usually harvested during this stage. The longer the green bean matures, the darker its color becomes.
Bursting Pods and New Beans
If not harvested before the bean plant fully matures, the bean pods will burst. When the pods burst, they will scatter seeds on the ground. These seeds will remain dormant until the next season, when they will integrate into the soil and begin to germinate, starting the life cycle again.