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Psophocarpus tetragonolobus
Fabaceae FAMILY

Psophocarpus tetragonolobus

Psophocarpus tetragonolobus

Edibility
5/5
Medicinal
0/5

Safety & Hazards

None known

Cultivation Details

HabitPerennial Climber
Growth—

Winged bean is a plant mainly of the humid lowland tropics, though it can also be grown al low elevations in the subtropics and up to 2,000 metres in the tropics. It is more problematic in temperate zones since most varieties will only flower when daylight hours are around 12 per day and so the plant will often not start flowering until near the end of summer[1]. However, day-neutral varieties are being developed that will flower earlier in the summer in northerly and southerly latitudes[2]. The plant grows best in areas where annual daytime temperatures are within the range 18 - 30°c, but can tolerate 14 - 40°c[3]. The plant can survive temperatures down to about 3°c[3]. It prefers a mean annual rainfall in the range 1,000 - 2,500mm, but tolerates 500 - 4,100mm[3]. A dry period when the plant is flowering and when the seed is ripening is beneficial[4]. Grows best in a sunny position[3]. Prefers a well-drained loamy slightly acidic soil, but there are cultivars suitable for many soil types[2, 4]. Tolerates heavy soils[1] but dislikes wet soils[2]. Prefers a pH in the range 5.5 - 7, tolerating 4.3 - 8.5[3]. Dislikes drought[2]. Most varieties will only flower when daylight hours are around 12 per day[1] but day-neutral varieties are being developed that will flower in the summer in northerly and southerly latitudes[2]. Plants are also slightly more tolerant of longer days in their second and subsequent seasons of growth[4]. Plants take 60 - 80 days from sowing to the first harvest of seedpods, the plants can continue to yield for a considerable period[2, 4]. Mature tubers can be harvested 120 - 240 days from sowing[2]. Seeds take 6 - 9 months to mature[4]. Yields can be very high - up to 35 tonnes of green pods per hectare can be produced; 1 - 2 tonnes of seed (if not many of the pods are harvested); plus 2.5 - 6 tonnes of tubers[4]. Pod removal stimulates tuber production, but growing the plants for seed reduces tuber yield[4]. There are many named varieties[5, 4, 6]. The plant is very disease resistant[7]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[2].

Propagation

Pre-soak the seed for 12 hours in warm water and sow in early spring in a warm greenhouse. Place two or three seeds in each pot, thinning to the strongest plant. Plant them out in late spring or early summer, after the last expected frosts and give them the protection of a cloche or cold frame until they are growing away strongly[8]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Psophocarpus+tetragonolobus>

Pollinators

Bees, Self

References

  1. [1]Oriental Herbs and Vegetables, Vol 39 No. 2. — Brooklyn Botanic Garden · Brooklyn Botanic Garden · 1986 · ISBN - ↩︎A small booklet packed with information.
  2. [2]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  3. [3]Ecocrop — http://ecocrop.fao.org/ecocrop/srv/en/home ↩︎Basic information on a wide range of useful plants, plus details of environmental needs where available.
  4. [4]Vegetables in the Tropics — Tindall. H. D. · MacMillan, Oxford. · 1983 · ISBN 0-333-24268-8 ↩︎An excellent, in-depth look at the main vegetable crops that can be grown in the Tropics, plus many less well-known plants.
  5. [5]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
  6. [6]Cornucopia II — Facciola. S. · Kampong Publications, California. · 1998 · ISBN 0-9628087-2-5 ↩︎The second edition of an excellent guide to the edible uses of plants, though it does not give any details of cultivation etc.
  7. [7]Wonder Crops. 1987. — Natural Food Institute, ↩︎Fascinating reading, this is an annual publication. Some reports do seem somewhat exaggerated though.
  8. [8]Glossary of Indian Medicinal Plants (Including the Supplement). — Chopra. R. N., Nayar. S. L. and Chopra. I. C. · Council of Scientific and Industrial Research, New Delhi. · 1986 · ISBN - ↩︎Very terse details of medicinal uses of plants with a wide range of references and details of research into the plants chemistry. Not for the casual reader.
  9. [9]Protabase - Plant Resources of Tropical Africa. — http://www.prota.org ↩︎An excellent on-line database with detailed information on over 3,200 species of useful plants of Africa.
  10. [10]Sturtevant's Edible Plants of the World. — Hedrick. U. P. · Dover Publications · 1972 · ISBN 0-486-20459-6 ↩︎Lots of entries, quite a lot of information in most entries and references.
  11. [11]Dictionary of Economic Plants. — Uphof. J. C. Th. · Weinheim · 1959 · ISBN - ↩︎An excellent and very comprehensive guide but it only gives very short descriptions of the uses without any details of how to utilize the plants. Not for the casual reader.
  12. [12]A Dictionary of Plants Used by Man. — Usher. G. · Constable · 1974 · ISBN 0094579202 ↩︎Forget the sexist title, this is one of the best books on the subject. Lists a very extensive range of useful plants from around the world with very brief details of the uses. Not for the casual reader.
  13. [13]The Useful Plants of the Island of Guam — Safford W.E. · Smithsonian Institute; Washington. · 1905 · http://www.biodiversitylibrary.org/ ↩︎A very comprehensive, if rather dated, guide to the plants of Guam. It can be downloaded from the Internet.
  14. [14]Tropical Food Gardens — Norrington. L. · Bloomings Books (Melbourne) · 2001 · ISBN 1-876473-41-x ↩︎Excellent little book giving some basic information on a range of plants.
  15. [15]A Revision of Psophocarpus (Leguminosae-Papilionoideae-Phaseoleae) — Verdcourt B. & Halliday P. · 1978 · http://10.2307/4109575 ↩︎
  16. [16]Edible Leaves of the Tropics — Martin. F. W.; Ruberte. R. M. & Meitzner. L. S. · Echo. USA. · 1998 · ISBN 0-9653360-1-8 ↩︎A terse guide, giving reasonable detail on the more common leaf crops and brief information on a wide range of lesser known plants.