Bixa commonly known as mrangi or annatto, is a perennial shrub grown mainly for its natural red pigment called bixin. Farmers grow it as a cash crop because it generates income in dry and marginal areas where few other crops perform well. The crop does not provide direct nutrition, but it plays a strong industrial role. Industries extract its pigment and use it as a natural colourant in food, cosmetics, and pharmaceuticals. In Kenya, it grows mainly in Kwale County, Kilifi County, and Lamu County, with expansion into semi-arid counties such as Tana River County, Taita Taveta County, Kitui County, and Makueni County.
Varieties
Farmers mainly grow local coastal landraces of Bixa orellana. These types tolerate heat, drought, and poor soils, and they establish easily under low-input systems. Improved selections also exist from research and private nurseries, focusing on higher bixin content, better yield, and more uniform growth. Local landraces suit coastal and semi-arid regions, while improved types perform better under managed conditions. Overall, yield depends on management, but improved lines generally produce more seed and pigment.
Climate & Soil
Bixa grows best in warm temperatures between 25°C and 38°C. It performs well under rainfall of 1,250 mm to 2,000 mm annually, although it survives in drier areas once established. The crop grows from sea level up to about 2,000 metres above sea level. It prefers well-drained sandy loam or loam soils and performs best at a pH of 5.5 to 7.5. Good drainage is essential because waterlogging reduces growth and yield.
Propagation & Planting
Farmers propagate bixa mainly through seeds, although some use stem cuttings. They raise seedlings in nurseries for about four months until they reach 15–25 cm in height. Germination takes 8–10 days under good conditions. Farmers transplant seedlings at the onset of rains to improve survival. They use spacing of 3 m by 3 m to allow proper canopy development and airflow. They also plant at the same depth as in the nursery to avoid stem rot. Early mulching and protection from livestock improve establishment.
Field Management & Harvesting
Farmers weed regularly, especially during early growth stages, to reduce competition. They apply mulch to conserve moisture and improve soil conditions. Young plants may need irrigation during dry spells, although mature plants are drought tolerant. Farmers mainly use farmyard manure to improve soil fertility. They prune plants to shape the canopy and improve harvesting efficiency. Harvesting starts about three years after planting when capsules dry and produce a rattling sound. Farmers sun-dry capsules, thresh them to remove seeds, and dry seeds further before storage.
Nutritional Value
Bixa has no direct nutritional use as a food crop. However, its seeds contain carotenoids, mainly bixin and norbixin. These compounds have antioxidant properties and are widely used as natural food colourants. They support health indirectly by replacing synthetic additives in processed foods. The crop has no edible parts for human consumption in Kenya.
Uses & Market Potential
Industries use bixa pigment in food products such as butter, cheese, oils, and beverages. They also use it in cosmetics like lipsticks, soaps, shampoos, and hair products. Pharmaceutical companies use it for capsule coating and colouring. Farmers sell dried seeds to local traders and aggregators, especially in coastal regions. Kenya also exports bixa to Europe, Asia, and North America, where demand for natural colourants continues to grow. Value addition through drying, cleaning, grading, and aggregation improves farmer earnings. Overall, bixa offers strong market potential due to rising global demand for natural and clean-label products.