Lupinus albus Seeds | White Lupine
LATIN NAME: Lupinus albus
COMMON NAME: White Lupine
Plant Profile
White lupin is an upright annual legume, 60-120 cm tall, with palmate leaves of seven to nine leaflets and dense spikes of white, pea-like flowers. The pods that follow are flat and hairy, carrying four to six large flat seeds, and the whole plant has the coarse, robust look of a field crop rather than a garden flower.
It has been grown for three thousand years as a green manure, a forage crop and a pulse. The seed is high in protein, around 35 per cent, and low in starch, which is why lupin flour appears in modern gluten-free baking.
The species comes from the Mediterranean basin and the Nile valley, and it is one of four lupins cultivated for seed, alongside the yellow, blue and Andean types. Its tolerance of lime is better than theirs, which is why it is the lupin grown on alkaline soils in Europe.
Science & Biotechnology
Lupins fix nitrogen through a symbiosis with Bradyrhizobium bacteria in root nodules, and a good crop can leave 100-200 kg of nitrogen per hectare in the soil. That is why white lupin is used as a break crop in cereal rotations across Europe and Australia.
The seed also contains quinolizidine alkaloids, chiefly lupanine, which are bitter and toxic to livestock and to people above a threshold. Modern sweet varieties carry less than 0.02 per cent alkaloid and are safe to eat; bitter types must be soaked and boiled repeatedly to leach the compounds out.
White lupin has a further trick: cluster roots. On phosphorus-poor soil it produces dense bottlebrush clusters of rootlets that exude organic acids, dissolving phosphate that other crops cannot reach. That adaptation is being studied as a way to reduce fertiliser use.
Uses & Benefits
As a garden plant, white lupin is grown for nitrogen fixation, for early bee forage and for the seed, which can be used as a protein crop or left for poultry. It is also a handsome border plant, with white spikes that stand well above the foliage in June.
In the kitchen the sweet-seeded varieties are used as lupin flour, as a snack after brining, and in the Mediterranean as a pickled pulse sold in jars. In agriculture the plant is a forage and a green manure, cut before the pods fill and dug in. Commercially the crop is grown on a large scale in Australia and northern Europe for animal feed and for human food ingredients.
Growing from Seed
Sow direct in spring, 2 cm deep, once the soil is above 8°C, at 20 cm apart in rows 40 cm apart. Lupins have a taproot and resent transplanting, so direct sowing is best. Germination takes ten days to two weeks; scarify the seed lightly with sandpaper if the packet is old.
The plant prefers light, lime-rich soil and full sun, and it will not tolerate waterlogging. Inoculate the seed with the correct Bradyrhizobium if the soil has never grown lupins. Weed early, since the seedlings are slow. Harvest pods when they rattle, and dry the seed fully before storing. For green manure, cut the plants at flowering and dig them in within a day.
Our Take
A crop and a flower at once, useful for the soil and worth growing for the white spikes even if the seed never reaches the kitchen.
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