The common bean is one of the main food crops globally. Bush varieties reach 20-60cm while climbing (or “pole”) varieties reach up to 3m in height. Depending on the variety, common beans are grown for their green pods and/or mature, dry seeds.
Common beans originated in the Andes region with probable introgressions from Central America. Radio carbon dating identifies the species as being 7,000 years old.
Since the early 1900’s, new varieties of both bush and pole beans, stringless and tender, have been developed so the older name, “string bean” no longer applies. The spent vines can be used as mulch, livestock food or cultivated into the soil.
Beans can be grown in a wide range of soils, preferring a well-drained friable soil, in full sun with a pH of 5.5 to 7.0. They should be planted after all danger of frost is past. Beans have indeterminate flowering so they need to be harvested frequently as they continue to bear over a longer period of time. Seeds should be planted about 2-3 cm (1 in) deep, in hills with 5-6 seeds to hill and 100 cm (39 in) between hills. They can also be planted in rows with 10 cm (4 in) between seeds and 120 cm (4 ft) between rows. In either arrangement, tall, sturdy support is necessary. Regular watering of 2.5 cm (1in) per week will give good results. They will do well in the tropics when planted at elevations between 1000-3000 m (3280-9840 ft).
Harvesting and Seed Production
For consumption as a fresh bean, the pods should be picked often, selecting those with well developed seeds, but not yet tough. To save seeds as a dry bean, or for planting, allow pods to dry on the plant. Pick dried pods, and store in a cool, dry location until needed for the next planting season.
Pests and Diseases
Long periods of wet weather may produce Sclerotia, a white mold appearing on the leaves. Potato leafhopper, Mexican bean beetle, bean leaf beetle and spider mite can also create problems. Damping-off can be avoided by planting in soils that have warmed to 15º C (60º F) and using large, vigorous and fungicide-treated seed. Seed maggots may attack seeds at germination. Treating the seeds with insecticide controls this problem.
Cooking and Nutrition
Beans are a good source of minerals and some vitamins if not overcooked. Eat beans raw, lightly cooked over steam, sautéed or added to a stir-fry. When home canned beans are to be served for a meal, they should be brought to a boil and simmered for 10 min. uncovered to kill any bacteria left from improper canning methods. Green beans freeze well.