Indigofera arrecta

Cultivation Details

A plant of the moist tropics, where it is found at elevations from 300 - 2,700 metres. It grows best in areas where annual daytime temperatures are within the range 22 - 30°c, but can tolerate 16 - 36°c^[1]. It can be killed by temperatures of °c or lower^[1]. It prefers a mean annual rainfall in the range 1,700 - 2,200mm, but tolerates 400 - 4,300mm^[1]. Prefers a hot, moist climate and a position in full sun^[2]. Succeeds in a range of soils^[1]. Prefers a pH in the range 5 - 6, tolerating 4.5 - 6.5^[1]. Plants can tolerate up to two months of waterlogging^[2]. Plants can commence flowering 3 months after sowing the seed^[3]. Branches are harvested, usually early in the morning, when the plants are 4 - 5 months old and the crop has made a closed stand. This is usually also the flowering stage. About 3 - 4 months later the plants can be cut again; a crop can be harvested three times a year^[2]. The total life span for dye crops is 2 - 3 years, whilst for cover crops it is 1.5 - 2 years^{[2, 1]}. Indigo is harvested only once when grown on paddy soils because the plants must give way for the next rice crop^[2]. The yield of this species is higher than from any other species of Indigofera. Annuals yields of 22 - 100 tonnes green matter per ha have been reported in India; the recorded output of indigo cake is 137 - 325 kg/ha per year^[2]. Natural hybridizations between Indigofera arrecta and Indigofera tinctoria do occur and especially in W Africa plants are often difficult to be assigned to one of the two taxa^[4]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby^[5].