How to grow Vigna unguiculata or cowpea in your garden
Vigna unguiculata or cowpea originated in Africa, where a large genetic diversity of wild types occurs throughout the continent, southern Africa being richest. It has been introduced in Madagascar and other Indian Ocean islands, where it is sometimes found as an escape from cultivation.
Cowpea is the preferred pulse in large parts of Africa. The mature seeds are cooked and eaten alone or together with vegetables, spices and often palm oil, to produce a thick bean soup, which accompanies the staple food (cassava, yam, plantain).
The leaves and the immature seeds and pods of cowpea are eaten as vegetables. Cowpea leaves are served boiled or fried and are usually eaten with a porridge. The leaf may be preserved by sun-drying or boiling and then sun-drying to be used during the dry season. Leaves to be preserved for later use are generally plucked towards the end of the season. It is believed that leaves developed towards the end of the season are tastier as they tend to grow under conditions of stress.
Cowpea is used as fodder in West Africa, Asia (especially India) and Australia; it is used for grazing or cut and mixed with dry cereals for animal feed. In the United States and elsewhere cowpea is grown as a green manure and cover crop. In Nigeria special cultivars are grown for the fibre extracted from the peduncle after retting; the strong fibre is especially suitable for fishing gear, and produces a good-quality paper. The dry seeds have been used as coffee substitute.
Various medicinal uses of cowpea have been reported: leaves and seeds are applied as a poultice to treat swellings and skin infections, leaves are chewed to treat tooth ailments, powdered carbonized seeds are applied on insect stings, the root is used as an antidote for snakebites and to treat epilepsy, chest pain, constipation and dysmenorrhoea, and unspecified plant parts are used as a sedative in tachycardia and against various pains.
Climbing, trailing or more or less erect annual or perennial herb, cultivated as an annual; taproot well developed, with many lateral and adventitious roots; stem up to 4 m long, angular or nearly cylindrical, slightly ribbed.
Growth and development
Germination of cowpea takes 3–5 days at temperatures above 22°C. The optimum temperature for germination is about 35°C. Flowers open in the morning and close before noon; they fall the same day. In dry climates cowpea is almost entirely self-pollinated, but in areas with high air humidity cross-pollination by insects may amount to 40%. Only fairly large insects are heavy enough to open the keel. The length of the reproductive period is very variable, with the earliest cultivars taking 30 days from planting to flowering, and less than 60 days to mature seeds. When leaves are harvested during the early growth stages, senescence starts 1.5–2 months after sowing and the plant dies after 3–4 months, depending on crop health and intensity of harvesting. Late cultivars with indeterminate growth take 90–100 days to flower and up to 240 days for last pods to mature. Cowpea forms N-fixing nodules with Sinorhizobium fredii and several Bradyrhizobium species.
Cowpea is a warm weather crop and this is the reason that it can survive in drought conditions also.
- Optimum temperature for germination is 12 to 15°C.
- Cowpea flourishes easily between the temperature of 25-35°C.
On other hand Cowpea cannot survive in the cold climate.
Month for planting summer season crop is February and March.
- Month for planting rainy season crop is June and July.
Cowpea requires sandy loamy soil with good water drainage capacity.
PH between 4.5-8.0 is needed for the cultivation of cowpea.
Fertilizers and Manure:
Quantity of FYM – 10-15t/ha
- Quantity of Nitrogen – 20kg/ha
Quantity of phosphorus – 40-50kg/ha
Purpose of cultivating cowpea can be different and according to that there are different rates of seeds:
- To use it as grain, the price of seeds are 15-20kg/ha.
- If we are using it as fodder crop then the price would be 35-40kg/ha.
To use it as green pod, then the price would be 20-25kg/ha.
Space required in summer season is 30×10cm.
Space required for rainy season is 45×10cm.
Cowpea requires around 3 to 4 irrigations.
- Soil and climate are major factors but generally 300-400mm water is required for the cultivation of cowpea.
On other hand, in season of summer more irrigation (4-5 irrigations) is required because of high temperature and low humidity.
Harvesting time of cowpea as vegetable is 45 to 90 days after sowing.
- On the other hand harvesting time of cowpea as grain is 90 to 125 days after sowing.
- Before storage, threshed crop must be dried in the heat of sun.
Normally cutting of the crop should be done in 40 to 45 days after sowing the seeds.