Confusion often arises when comparing crops that grow underground, like potatoes, to those that develop above the soil. Many people wonder if pinto beans are similar to subterranean crops such as peanuts. This article clarifies the growth cycle of the pinto bean, addressing whether the edible part develops beneath the soil or in the open air.
The Direct Answer: Above Ground
The pinto bean, which is the edible seed of the plant, does not grow underground. It develops inside a protective casing called a pod, produced entirely above the soil line on the plant’s stem and branches. Unlike root vegetables such as carrots or potatoes, the plant is not harvested by digging up an underground part. This growth pattern distinguishes pinto beans from peanuts, which push their fertilized ovaries into the soil to mature. Pinto beans (Phaseolus vulgaris) remain exposed to the air throughout their entire development until harvest.
Anatomy of the Bean Plant
Pinto beans are botanically classified as seeds, which are the reproductive structures of the plant. These seeds mature within the pod, which is the plant’s fruit, forming after the plant produces small white or yellow flowers. The plant’s roots, which are the only structures that grow underground, serve the function of anchoring the plant and absorbing water and nutrients. Like all legumes, pinto bean roots have a symbiotic relationship with bacteria that fix atmospheric nitrogen directly into the soil. This process enriches the surrounding dirt, but the beans develop from the fertilized flower high above the soil.
Growth Habit and Harvesting
Pinto bean plants are cultivated in two primary forms, both keeping the developing beans off the ground. Bush varieties are determinate, growing low and compact, reaching a height of about 18 to 20 inches. Pole varieties are indeterminate vining plants that climb supports like trellises, often reaching heights of six feet or more. Both types require a long, warm season, typically taking 90 to 150 days from planting to final harvest.
For the dried beans commonly bought in stores, the harvesting process requires the pods to dry completely on the vine. As the plant nears the end of its life cycle, the green pods turn a brittle, pale yellow or brown color. This desiccation ensures the seed inside is fully mature and ready for long-term storage. Growers then collect the dried pods, or sometimes pull the entire plant to finish drying, and shell the hard, speckled beans from the husk.