The basics of growing lupins

Lupins are planted in both the winter and summer rainfall regions of South Africa. They are particularly popular in the coastal areas of the Western Cape, where they are used as a pasture crop for sheep production

Lupins (Lupinus spp.) can play an important role in conservation agriculture-based crop-pasture rotations. Most lupins are grown for their high-quality seed, which is used as a protein and energy concentrate in livestock feed rations.

Also commonly known as blue bonnets, and sometimes grown as ornamental plants, these mostly herbaceous perennial plants can be between 0,3m and 1,5m tall, with some growing up to 3m.

They have soft green to grey-green leaves which may be covered in silvery hairs. The leaf blades are usually divided into five to 28 leaflets.

The flowers, each of which is 1cm to 2cm long, are produced in dense or open whorls on an erect spike.

The species of lupins important for agricultural purposes are the yellow lupin (L. luteus), the white lupin (L. albus), also known as the Italian lupin, and the blue lupin (L. angustifolius).

Alkaloids in lupins determine how sweet or bitter the plant is. White lupins are sweet (tasty), and their seeds are used for animal feed. L. angustifolius is planted for grazing. Animals eat only the older leaves and avoid the growth points. This species establishes more readily than other legumes, write Dr Wayne Truter et al in their article on lupins for Grain SA.

Lupins prefer a slightly acidic and poorer soil. Like other legumes, lupines fix nitrogen (N) from the atmosphere into ammonia via a rhizobium-root nodule symbiosis, fertilising the soil for other plants. This makes them extremely valuable to the next crop planted in the land.

L. angustifolius is the most common species planted in the Western Cape, and does well in sandy soils.