Kidney beans plants are legumes, plants which produce pods that split in two to release seeds, belonging to the species Phaseolus vulgaris L. The life cycle of many beans are very similar. Kidney beans are easy to grow, but very susceptible to frost damage, and should not be planted outside until after the chance of frost has passed.
Seed and Germination
Kidney bean seeds are dried, and can be planted in this state, but germination will slow considerably. Soaking the seeds in water for 12 to 24 hours up to 24 hours in advance of planting will increase germination speed to 10 to 16 days, depending on weather and climate. Seeds should be planted at a depth of 1 inch, and watered evenly whenever the soil feels dry to the touch.
The hypocotyl (shoots) are bent over at first, and begin a process known as phototropism, which is the process during which the stem straightens and grows upward, toward the light. Two small leaves are produced, which continue to increase in size as the root system develops more fully. Seedlings are especially vulnerable to frost, and must be kept indoors to protect against cold weather, unless all danger of frost has completely passed.
Kidney beans take approximately six weeks to mature from seedlings and begin producing flowers. During this period, the root systems mature and anchor into the soil of their permanent growing area, and the plant produces multiple leaves from the main stem. Kidney bean plants generally grow to 18 inches high. Kidney bean bushes should be spaced 12 to 18 inches apart.
Flowers begin to form once the plant has matured, from the junction of stem and leaves. Once pollinated, the flower withers and dies, revealing a tiny kidney bean pod. Young kidney bean pods are usually pale green at this stage, developing their distinctive coloring as they grow. According to "The Allotment Book" by Andi Clevely, a 20-foot row of a pole variety of kidney beans can give a 15 lb. fruit yield. He also states that pole varieties produce a larger quantity of beans over a longer period, in comparison with bush varieties of kidney bean which tend to produce all their pods over the course of around three weeks.
Kidney bean plants do not cross-pollinate between different varieties or other bean types, and thus are safe to save seeds from. To gather seed for the following growing season, leave some pods to mature on the plants as fruit production slows. The pod wrinkles, hardens and loses its color. Remove the dried pods from the plant, shell the beans and leave them to air dry. The beans dry out and dehydrate, becoming small and hard. These dried beans can be used as seed the following year.