Green beans, also called kidney beans and kidney beans, are leguminous, annual, twining or nearly erect herbs of kidney beans. Stems pubescent or glabrous when old. Pinnate compound leaves; Stipules lanceolate, small leaves broadly ovate or ovoid-rhombic, lateral oblique, raceme shorter than leaves, with several flowers at the top of inflorescence; Bracteoles are ovoid, with several raised veins, calyx cup-shaped, corolla white, yellow, violet or red; Wing flap obovate, style squashed.

The pod is banded, slightly curved, the seeds are oval or kidney-shaped, white, brown, blue or spotted, and the hilum is usually white. Bloom in spring and summer.

Green beans are one of the most widely cultivated crops in the genus Phaseolus, with tender pods for vegetables, with more than 500 varieties. Therefore, there are great variations in plant shape, flower color and size, pod and seed shape and color, and different flavors.

Origin and habitat of green beans:

Native to America and cultivated in China. It has been widely planted in tropical to temperate regions. Green beans are warm and frost-intolerant, and the suitable growth temperature is 15-25℃, and the low temperature below 10℃ or the high temperature above 30℃ will affect their growth and normal pod setting.

At the high temperature above 32℃, the physiological metabolism is disordered, and it is easy to drop flowers and pods, or the pods are small and deformed. Green beans like light and require high light intensity.

The saturated light intensity is 20,000-25,000 lux, and the compensation point is 1500 lux. Green beans are extremely sensitive to light changes. When the light is weak, the plants grow in vain, the number of stems and leaves decreases, and the pod setting rate decreases when the light is weak at flowering stage, and the flowers will drop on cloudy days for two consecutive days.