Kidney beans are dry beans. Others in this category are pinto beans, navy beans and black beans. All dry beans belong to the same species, Phaseolus vulgaris L. The life cycles of many bean plants and seeds are strikingly similar.
Kidney bean seeds are the kidney beans themselves. The bean seeds are planted in the ground in areas where a short growing season exists; they can be started indoors about six weeks prior to the last projected frost. When planting outdoors, the soil temperature should be a consistent 65 degrees. Bean seeds should be spaced 12 inches apart in nutrient-rich soil at a depth of approximately 1 inch. Sprouts will emerge in four to 10 days if temperatures remain above 65 degrees.
The seedlings will grow steadily, filling out into lush densely leaved bush. It will take more than two months for the plants to reach maturity and blossom. Flowers are the sign that bean pod production is about to commence. Once pollinated, the blossoms fall away and tiny pods begin to form.
Dry beans grow on bushy plants that produce one crop per season. With a total growing time of 90 to 100 days, it is not usually possible to plant a second crop. Mature height is about 30 inches and width is about 18 inches. As long as temperatures remain consistently warm, bean pods should develop about 75 to 90 days later.
The pods appear, often around 45 to 60 days, after the seedlings emerge. Bean pods mature quickly and will take on a papery, dried out look. They are not ready to harvest until the texture is so hard that biting does not leave an imprint. Once the seeds have reached this phase, it is time to harvest the beans.
Threshing by hand is the most common way to remove the seeds from the pods. It entails pulling the plants up in their entirety and using one of two methods. Hold a handful of the plants over a clean dry trash can and shake the bundle vigorously against the insides of the can, allowing the beans to fall to the bottom. Or place the dried out plants inside a cloth bag such as a pillow case and lightly step on the bag to loosen the beans. No matter which method is used, simply remove the plant debris and pick out the beans.