Vigna unguiculata Seeds | Cowpea Sinensis
LATIN NAME: Vigna unguiculata
COMMON NAME: Cowpea
Plant Profile
Cowpea is a warm-season annual with three leaflets, a taproot that goes down a metre, and a habit that ranges from a compact bush of forty centimetres to a trailing vine two metres long. It is the grain legume of the Sahel, grown from Senegal to Sudan on land too dry for groundnut and too poor for maize.
The species came out of Africa and crossed the Atlantic with the slave trade, which is why it appears in the cooking of the American South and of Bahia under names that have nothing to do with one another. Black-eyed pea, crowder pea, niebe and caupi all describe the same plant, and the seed coat may be cream with a dark eye, brown, or almost black.
Science & Biotechnology
Cowpea fixes nitrogen through the usual rhizobial partnership, but the quantities are modest, typically twenty to eighty kilograms per hectare, and the plant often nodulates poorly where the soil has no compatible strain. Inoculation at sowing is worth the cost on new ground.
The trait that matters most in the field is heat. Cowpea sets pods at night temperatures above twenty-five degrees, where common bean sheds its flowers, and its pollen stays viable at forty degrees. Breeding work has concentrated on bruchid resistance, since a storage beetle can turn a sack of seed into dust in three months, and on resistance to the parasitic weed Striga.
Uses & Benefits
Green cowpea is eaten as a vegetable in West Africa, boiled with palm oil, and the young leaves are cooked like spinach in the same regions. The dried seed goes into akara, the fritter sold at roadsides from Lagos to Salvador, where the peeled seed is ground with onion and fried in dendê oil.
The haulm is valuable fodder, and in the dry savanna it is often worth as much as the grain. Cowpea hay carries twelve to eighteen per cent protein and is cut before the pods fill, a practice that costs some seed yield and pays for itself in milk.
Growing from Seed
Sow direct once the soil reaches eighteen degrees, two to three centimetres deep, in rows sixty centimetres apart with the seed ten centimetres apart. Cowpea resents transplanting, so raise it where it is to grow. Germination takes five to seven days in warm ground.
Choose the habit to suit the space: bush types need no support and fit a small plot, while the trailing types yield more but will smother a neighbour. Pick pods every few days, since a dry pod shatters and scatters. For seed, leave the crop until the pods rattle and store it in a sealed jar with a pinch of diatomaceous earth, because the bruchid arrives with the harvest.
Our Take
The most heat-tolerant grain legume a home garden can grow, and the one that keeps producing when beans have given up. Pick it young for the table and let the rest dry.
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