The kidney bean is a variety of the common bean, Phaseolus vulgaris, an annual herbaceous plant cultivated globally for its edible dry seeds. Its name is derived from its distinct shape and color, which closely resembles a human kidney. This widely consumed legume is a product of millennia of cultivation. This article explores the geographical origins of the kidney bean, its required growing environment, and the cycle of cultivation and harvest.
Historical Origins and Global Production Hubs
The common bean (Phaseolus vulgaris) originated in the Americas, domesticated in two primary centers: Mesoamerica (Mexico and Central America) and the Andes (South America) over seven millennia ago. Archeologists found evidence of large-seeded varieties, similar to the modern kidney bean, in the highlands of Peru dating back to 2300 BC. Smaller-seeded varieties were found in Mexico, dating to 300 BC.
The global spread of the common bean occurred after the arrival of Europeans in the New World, becoming a staple crop through the widespread exchange known as the Columbian Exchange. This movement introduced Phaseolus vulgaris to Europe, Africa, and Asia, where it adapted to diverse climates. Today, the common bean is grown on every continent except Antarctica.
While the bean is grown across many regions, the bulk of global production is concentrated in a few countries. India is the world’s leading producer of dry common beans, accounting for approximately 23% of the total global production. Other major commercial hubs include China, Myanmar, the United States, and Brazil, which supply a significant portion of the world’s dry bean market. When focusing specifically on dark red kidney beans, the United States, Argentina, Canada, and China account for the largest share of the commercial market.
Ideal Environmental Requirements for Growth
The kidney bean is a warm-season crop highly sensitive to cold temperatures and frost. A successful growing season requires a frost-free period, as light frost can damage the plants. The optimal air temperature range is between 65°F and 85°F (18°C and 29°C).
The soil must be warm before planting, ideally maintaining a temperature above 60°F (15°C) for strong germination and root development. Kidney beans require loose, well-drained soil, as the plant does not tolerate waterlogged conditions, which can lead to root rot. The preferred soil acidity is slightly acidic to neutral, with a pH range between 6.0 and 7.0.
Consistent moisture is necessary throughout the growing season, particularly during the flowering and pod-filling stages. The shallow root system makes the plant susceptible to overwatering, so the soil must be kept evenly moist but never soggy. Plants require at least six to eight hours of direct sunlight daily to properly photosynthesize and produce a yield.
Cultivation and Harvesting Cycle
Cultivation begins with direct seeding the beans into the soil, as kidney beans have shallow roots and do not transplant well. Planting occurs in the spring, only after the danger of the last frost has passed and the soil is warm. Seeds are usually sown about one to two inches deep.
The full growth cycle for the dried bean typically ranges from 90 to 120 days, depending on the variety and local climate. During this period, the plant produces its own nitrogen through a symbiotic relationship with soil bacteria, limiting the need for nitrogen fertilizers. The pods develop and the seeds inside mature.
Kidney beans are harvested when the pods are fully mature and completely dry on the plant. This is signaled when the pods turn a straw color, become brittle, and the seeds rattle inside. Farmers often pull the entire plant and allow it to finish drying before the beans are shelled and prepared for storage.