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Brassicaceae FAMILY

Brassica napus rapifera

Brassica napus rapifera

Edibility
4/5
Medicinal
2/5

Safety & Hazards

The oil contained in the seed of some varieties of this species can be rich in erucic acid which is used in industry but is toxic if consumed. However, modern cultivars have been selected for culinary use which are almost free of erucic acid[1].

Cultivation Details

HabitBiennial
Growth—

The swede is much cultivated in the temperate to subtropical zones. It grows best in areas where annual daytime temperatures are within the range 14 - 24°c, but can tolerate 5 - 35°c[1]. When dormant, the plant can survive temperatures down to several degrees below freezing, but young growth can be severely damaged at -1°c[1]. Very young plants are susceptible to cold damage, -4°c either killing or injuring seedlings, whereas -2°c has no affect when the plants are more than one month old[2]. It prefers a mean annual rainfall in the range 700 - 1,000mm, but tolerates 300 - 2,800mm[2, 1]. Succeeds in full sun in a well-drained fertile preferably alkaline soil[3, 4]. Prefers a stiff moist soil and a fairly high rainfall[3, 5, 6]. Another report says that it prefers a light but rich soil and an open sunny position[7]. Succeeds in any reasonable soil[8]. Sunny days and cool nights are favourable for plant growth[2]. Prefers a pH in the range 5.5 - 7, tolerating 4.2 - 8.2[2, 1]. There are several named varieties[9]. Plants take around 180 days from sowing to first harvest of the mature roots, generally 4 - 6 weeks longer to mature than turnips[9, 1]. The plant is somewhat hardier than turnips and in much of the temperate zone the roots can usually be left outdoors all winter and harvested as required, though in cold winter areas it would be safer to harvest the roots and store them. Swede is 70% self-pollinating and 30% cross-pollinated. Even if wind and insects are absent, seed are still produced. Seed yield increases when honeybees fertilize the flowers[2].

Propagation

Seed - sow mid spring to early summer in situ. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-20. <temperate.theferns.info/plant/Brassica+napus+rapifera>

Pollinators

Bees, Self

References

  1. [1]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.
  2. [2]Handbook of Energy Crops — Duke. J. · - · 1983 · https://hort.purdue.edu/newcrop/duke_energy/dukeindex.html · ISBN - ↩︎Published only on the Internet, excellent information on a wide range of both temperate and tropical plants.
  3. [3]New Vegetable Growers Handbook. — Simons. · Penguin · 1977 · ISBN 0-14-046-050-0 ↩︎A good guide to growing vegetables in temperate areas, not entirely organic.
  4. [4]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.
  5. [5]Companion Planting for Successful Gardening. — Riotte. L. · Garden Way, Vermont, USA. · 1978 · ISBN 0-88266-064-0 ↩︎Fairly good.
  6. [6]Comfrey Report. — Hills. L. · Henry Doubleday Research Ass. ↩︎A small booklet giving a fairly comprehensive guide to the uses of comfrey.
  7. [7]Vegetables — Phillips. R. & Rix. M. · Macmillan Reference Books, London. · 1995 · ISBN 0 333 62640 0 ↩︎Excellent and easily read book with good information and an excellent collection of photos of vegetables from around the world, including many unusual species.
  8. [8]Salads all the Year Round. — Larkcom. J. · Hamlyn · 1980 ↩︎A good and comprehensive guide to temperate salad plants, with full organic details of cultivation.
  9. [9]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.
  10. [10]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  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]Economic Botany. — Hill. A. F. · The Maple Press · 1952 · ISBN - ↩︎Not very comprehensive, but it is quite readable and goes into some detail about the plants it does cover.
  13. [13]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.
  14. [14]Plants and People of Nepal — Manandhar. N. P. · Timber Press. Oregon. · 2002 · ISBN 0-88192-527-6 ↩︎Excellent book, covering over 1,500 species of useful plants from Nepal together with information on the geography and peoples of Nepal. Good descriptions of the plants with terse notes on their uses.
  15. [15]Hamlyn Encyclopaedia of Plants. — Triska. Dr. · Hamlyn · 1975 · ISBN 0-600-33545-3 ↩︎Very interesting reading, giving some details of plant uses and quite a lot of folk-lore.
  16. [16]The Herb Book. — Lust. J. · Bantam books · 1983 · ISBN 0-553-23827-2 ↩︎Lots of information tightly crammed into a fairly small book.
  17. [17]Plants for Man. — Schery. R. W. ↩︎Fairly readable but not very comprehensive. Deals with plants from around the world.
  18. [18]Plants Consumed by Man. — Brouk. B. · Academic Press · 1975 · ISBN 0-12-136450-x ↩︎Readable but not very comprehensive.
  19. [PFAF]Plants for a Future — pfaf.org ↩︎