Green Bean

Sowing: Green beans are sown directly into the garden once all danger of frost has passed and the soil has warmed, since the seedlings resent being transplanted. Seed is set about an inch deep and roughly two inches apart, in rows 18 to 36 inches apart, and germinates best between 70°F and 80°F; below 60°F germination is slow or poor. Growers wanting a continuous supply make successive sowings into mid- or late summer, saved seed stays viable for about five years, and beans can follow a spring crop of lettuce, spinach, or peas in the same bed.

Care: Bush types stay compact at one to three feet tall, while climbing types need six to twelve feet of trellis or other support. Plants want full sun, since partial shade reduces yield, well-drained soil of average fertility around pH 6.0 to 6.8, and roughly an inch of water a week, applied early in the day and away from the foliage to limit disease. Mulching once the second set of true leaves appears helps hold soil moisture, and because the roots fix their own nitrogen through soil bacteria, added nitrogen fertilizer is unnecessary; inoculating seed with rhizobium can raise yields in soil new to beans.

Pests: Mexican bean beetles, aphids, leafhoppers, seedcorn maggots, and two-spotted spider mites all trouble the crop. Beetles and their eggs can be handpicked from small plantings, a hard spray of water dislodges aphids and mites, seedcorn maggots are discouraged by avoiding heavy manure or organic matter that attracts the egg-laying flies, and leafhoppers are harder to manage directly, stunting growth and spreading viruses as they feed.

Diseases: Bacterial blights, bean common mosaic virus, and white mold affect green beans, and all three worsen where foliage stays wet and plants are crowded. Watering early in the day, spacing plants for airflow, clearing weeds and fallen debris, and rotating beans out of a bed for three years all help limit their spread.

Disorders: Pod set often fails when temperatures climb above 90°F, and misshapen pods can follow from too little moisture, poor soil fertility, or insect feeding during bloom.

Snap or green beans are picked regularly while the pods are still young and tender, since frequent picking keeps the plants producing. Left longer, the same crop can instead be taken as shell beans once the seeds inside have filled out, or as dry beans once the pods and seeds have matured and dried on the plant.

Culinary: Green bean is grown chiefly for its edible pods and seeds, eaten fresh as young pods, as shell beans once the seeds have swelled, or dried as a mature bean. The dry seed is a significant source of dietary protein for people across Latin America, where it complements cereal-based diets.

Ornamental: Its bushy or climbing, vining habit also suits it to edible landscaping, with bush types grown in containers and climbing types trained up trellises or other vertical supports.

Green bean is native to tropical America and was brought into cultivation there in pre-Columbian times, with the crop domesticated independently at least twice, in the southern Andes and in Mesoamerica. Both domesticated lines descend from wild bean populations ranging from northern Mexico to northwestern Argentina that share a common ancestor in Ecuador and northern Peru. The species has been cultivated worldwide for more than 7,000 years, and hundreds of cultivars have since been selected across the regions where it is grown.