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Allium cepa - L.

Onion

Author	L.	Botanical references	200
Family	Alliaceae	Genus	Allium
Synonyms
Known Hazards	There have been cases of poisoning caused by the consumption, in large quantities and by some mammals, of this plant. Dogs seem to be particularly susceptible[76].
Range	W. Asia - Iran? The original habitat is obscure.
Habitat	Not known in the wild.
Edibility Rating	5 (1-5)	Medicinal Rating	3 (1-5)

Physical Characteristics

An evergreen Bulb growing to 0.6m.

The plant prefers light (sandy) and medium (loamy) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils and can grow in very alkaline soil. It cannot grow in the shade. It requires moist soil.

Habitats

Cultivated Beds;

Cultivars: (as above except)
'Perutile'

Edible Uses

Edible Parts: Flowers; Leaves; Root; Seed.

Bulb - raw or cooked. A very versatile food, the bulb can be 10cm or more in diameter and is widely used in most countries of the world. Eaten raw, it can be sliced up and used in salads, sandwich fillings etc, it can be baked or boiled as a vegetable in its own right and is also commonly used as a flavouring in soups, stews and many other cooked dishes. Some cultivars have been selected for their smaller and often hotter bulbs and these are used for making pickles. Leaves - raw or cooked[2, 37]. There are some cultivars, the spring onions, that have been selected for their leaves and are used in salads whilst still young and actively growing - the bulb is much smaller than in other cultivars and is usually eaten with the leaves. By successional sowing, they can be available at any time of the year. Flowers - raw. Used as a garnish on salads. The flowers are somewhat dry and are less pleasant than many other species[K]. The seeds are sprouted and eaten. They have a delicious onion flavour[K].

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Anthelmintic; Antiinflammatory; Antiseptic; Antispasmodic; Carminative; Diuretic; Expectorant; Febrifuge; Homeopathy; Hypoglycaemic; Hypotensive; Lithontripic; Skin; Stings; Stomachic; Tonic.

Although rarely used specifically as a medicinal herb, the onion has a wide range of beneficial actions on the body and when eaten (especially raw) on a regular basis will promote the general health of the body. The bulb is anthelmintic, anti-inflammatory, antiseptic, antispasmodic, carminative, diuretic, expectorant, febrifuge, hypoglycaemic, hypotensive, lithontripic, stomachic and tonic[4, 7, 21]. When used regularly in the diet it offsets tendencies towards angina, arteriosclerosis and heart attack[254]. It is also useful in preventing oral infection and tooth decay[254]. Baked onions can be used as a poultice to remove pus from sores[254]. Fresh onion juice is a very useful first aid treatment for bee and wasp stings, bites, grazes or fungal skin complaints[7, 201]. When warmed the juice can be dropped into the ear to treat earache[254]. It also aids the formation of scar tissue on wounds, thus speeding up the healing process, and has been used as a cosmetic to remove freckles[7]. Bulbs of red cultivars are harvested when mature in the summer and used to make a homeopathic remedy[232]. This is used particularly in the treatment of people whose symptoms include running eyes and nose[232].

Other Uses

Cosmetic; Dye; Hair; Polish; Repellent; Rust.

The juice of the plant is used as a moth repellent and can also be rubbed onto the skin to repel insects[7]. The plant juice can be used as a rust preventative on metals and as a polish for copper and glass[7]. A yellow-brown dye is obtained from the skins of the bulbs[141, 168]. Onion juice rubbed into the skin is said to promote the growth of hair and to be a remedy for baldness[7, 254]. It is also used as a cosmetic to get rid of freckles[7]. The growing plant is said to repel insects and moles[201]. A spray made by pouring enough boiling water to cover 1kg of chopped unpeeled onions is said to increase the resistance of other plants to diseases and parasites[201].

Cultivation details

Prefers a sunny sheltered position in a rich light well-drained soil[1, 16]. Prefers a pH of at least 6.5[200]. Plants tolerate a pH in the range of 4.5 to 8.3. Onions are best grown in a Mediterranean climate, the hot dry summers ensuring that the bulbs are ripened fully[200]. For best growth, however, cool weather is desirable at the early stages of growth[200]. Plants are frost-tolerant but prolonged temperatures below 10°c cause the bulb to flower[200]. Optimum growth takes place at temperatures between 20 and 25°c[200]. Bulb formation takes place in response to long-day conditions[200]. Plants are perennial but the cultivated forms often die after flowering in their second year though they can perennate by means of off-sets[1]. The onion was one of the first plants to be cultivated for food and medicine[244]. It is very widely cultivated in most parts of the world for its edible bulb and leaves, there are many named varieties capable of supplying bulbs all the year round[200]. This species was derived in cultivation from A. oschaninii[203]. Most forms are grown mainly for their edible bulbs but a number of varieties, the spring onions and everlasting onions, have been selected for their edible leaves. There are several sub-species:- Allium cepa 'Perutile' is the everlasting onion with a growth habit similar to chives, it is usually evergreen and can supply fresh leaves all winter. Allium cepa aggregatum includes the shallot and the potato onion. These are true perennials, the bulb growing at or just below the surface of the ground and increasing by division. Plants can be divided annually when they die down in the summer to provide bulbs for eating and propagation. Allium cepa proliferum is the tree onion, it produces bulbils instead of flowers in the inflorescence. These bulbils have a nice strong onion flavour and can be used raw, cooked or pickled. Onions grow well with most plants, especially roses, carrots, beet and chamomile, but they inhibit the growth of legumes[18, 20, 54, 201]. This plant is a bad companion for alfalfa, each species negatively affecting the other[201]. Members of this genus are rarely if ever troubled by browsing deer[233].

Propagation

Seed. Early sowings can be made in February in a greenhouse to be planted out in late spring. The main sowing is made in March or April in an outdoor seedbed, this bed must be very well prepared. A sowing can also be made in an outdoor seedbed in August of winter hardy varieties (the Japanese onions are very popular for this). These overwinter and provide an early crop of onion bulbs in June of the following year. Onion sets can be planted in March or April. Sets are produced by sowing seed rather thickly in an outdoor seedbed in May or June. The soil should not be too rich and the seedlings will not grow very large in their first year. The plants will produce a small bulb about 1 - 2cm in diameter, this is harvested in late summer, stored in a cool frost-free place over winter and then planted out in April. A proportion of the bulbs will run quickly to seed but most should grow on to produce good sized bulbs.

Cultivars

There are many named varieties of this annual vegetable, with new forms being developed each year. At present there is not time to enter these in the database and it is recommended that you consult the book 'The Fruit and Vegetable Finder' which is updated regularly and can be obtained from libraries. A few truly perennial forms have been entered and are listed on the following pages.

'Perutile'

This is a genuinely perennial form of A. cepa that rarely flowers, increasing mainly by division in much the same way as chives[50]. It is occasionally cultivated for its edible leaves. Plants usually produce fresh growth throughout the winter making this an ideal winter salad plant[K]. Bulb - raw or cooked. A nice onion flavour but rather small[K] Leaves - raw or cooked. A delicious taste, somewhat like spring onions[K]. The leaves are finer in texture and milder than the Welsh onion and are used in salads or added as a flavouring in cooked foods[183]. Flowers - raw. This plant rarely flowers.

Links

This plant is also mentioned in the following PFAF articles: Allium Species - the Perennial Onions, Alternative Edible Leaves, The Potted Garden.

References

[K] Ken Fern
Notes from observations, tasting etc at Plants For A Future and on field trips.

[1] F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaces in 1992 by a new dictionary (see [200]).

[2] Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972 ISBN 0-486-20459-6
Lots of entries, quite a lot of information in most entries and references.

[4] Grieve. A Modern Herbal. Penguin 1984 ISBN 0-14-046-440-9
Not so modern (1930's?) but lots of information, mainly temperate plants.

[7] Chiej. R. Encyclopaedia of Medicinal Plants. MacDonald 1984 ISBN 0-356-10541-5
Covers plants growing in Europe. Also gives other interesting information on the plants. Good photographs.

[16] Simons. New Vegetable Growers Handbook. Penguin 1977 ISBN 0-14-046-050-0
A good guide to growing vegetables in temperate areas, not entirely organic.

[18] Philbrick H. and Gregg R. B. Companion Plants. Watkins 1979
Details of beneficial and antagonistic relationships between neighbouring plants.

[20] Riotte. L. Companion Planting for Successful Gardening. Garden Way, Vermont, USA. 1978 ISBN 0-88266-064-0
Fairly good.

[21] Lust. J. The Herb Book. Bantam books 1983 ISBN 0-553-23827-2
Lots of information tightly crammed into a fairly small book.

[37] Thompson. B. The Gardener's Assistant. Blackie and Son. 1878
Excellent general but extensive guide to gardening practices in the 19th century. A very good section on fruits and vegetables with many little known species.

[50] ? Flora Europaea Cambridge University Press 1964
An immense work in 6 volumes (including the index). The standard reference flora for europe, it is very terse though and with very little extra information. Not for the casual reader.

[54] Hatfield. A. W. How to Enjoy your Weeds. Frederick Muller Ltd 1977 ISBN 0-584-10141-4
Interesting reading.

[76] Cooper. M. and Johnson. A. Poisonous Plants in Britain and their Effects on Animals and Man. HMSO 1984 ISBN 0112425291
Concentrates mainly on the effects of poisonous plants to livestock.

[141] Carruthers. S. P. (Editor) Alternative Enterprises for Agriculture in the UK. Centre for Agricultural Strategy, Univ. of Reading 1986 ISBN 0704909820
Some suggested alternative commercial crops for Britain. Readable. Produced by a University study group.

[168] Grae. I. Nature's Colors - Dyes from Plants. MacMillan Publishing Co. New York. 1974 ISBN 0-02-544950-8
A very good and readable book on dyeing.

[183] Facciola. S. Cornucopia - A Source Book of Edible Plants. 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.

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. 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.

[201] Allardice.P. A - Z of Companion Planting. Cassell Publishers Ltd. 1993 ISBN 0-304-34324-2
A well produced and very readable book.

[203] Davies. D. Alliums. The Ornamental Onions. Batsford 1992 ISBN 0-7134-7030-5
Covers about 200 species of Alliums. A very short section on their uses, good details of their cultivation needs.

[232] Castro. M. The Complete Homeopathy Handbook. Macmillan. London. 1990 ISBN 0-333-55581-3
A concise beginner's guide to the subject. Very readable.

[233] Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990 ISBN 0 460 86048 8
A concise guide to a wide range of perennials. Lots of cultivation guides, very little on plant uses.

[244] Phillips. R. & Foy. N. Herbs Pan Books Ltd. London. 1990 ISBN 0-330-30725-8
Deals with all types of herbs including medicinal, culinary, scented and dye plants. Excellent photographs with quite good information on each plant.

[254] Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London 1996 ISBN 9-780751-303148
An excellent guide to over 500 of the more well known medicinal herbs from around the world.

Readers Comments

Plants for a Future does not verify the accuracy of reader comments, use at your own risk. In particular Plants For A Future can not take any responsibility for any adverse effects from the use of plants. You should always consult a professional before using plants medicinally.

Allium cepa

SATEJ D SUTAR Mon May 8 2006

SIR, i am working on the shelf life and preservation tecqunices of red onion and white onion .I WILL BE EXTREMELY THANKFUL TO YOU IF I GET SOME VALUABLE INFORMATION FROM YOU. YOUR'S SINCERELY SATEJ SUTAR MON 09 MAY 2006

Allium cepa

miranda Wed May 10 2006

a physical plant description would be much appreciated.

Allium cepa

hadeel magdi Mon Jun 26 2006

iam a student in faculty of pharmacy i need more information about active constituents and toxicity but all information included are perfectly collected.

Allium cepa

Mark Moodie Wed Oct 18 2006

Considera Homoeopathic use of this and many other substances for use directly on plants and soils

Allium cepa

Vishvas Wed Jan 17 2007

Its good effort . But update with some more links

National Research Centr For Onion & Garlic

Allium cepa

muh'd salisu Thu Jan 25 2007

i'm researcher working on the antibaterial effects of this plant in treating tooth ache

Allium Species - the Perennial Onions

M Shahid Homeopath D.H.M.S University Of Greenwich England Tue Feb 12 2008

Allium cepa aslo know as Liliaccae is being used in Homeopathy as a very strong remedy for colds and flu - Common cold with much sneezing, watering of eyes and acrid nasal discharge. Also for hayfever - Nose and eyes stream. Frequent and severe sneezing. Worse in the morning, indoors. For more information visit

Allium cepa

christina venske Wed Jun 4 2008

Can I grow the plant from seed and eat to help ease my hayfever symptoms. Do you have a specific name for the type of bulb to grow to treat the symptoms, it ranges from allium cepa (Aggregatum gp)'Ambition Shallot' TO allium cepa 'Yellow Utah jumbo'. Could you suggest a variety worth trying ??

Allium cepa

virat abhishek,punjab,india Sun Aug 31 2008

sir,i,m an undergraduate of food science & i,m seeking for preservation methods of onion.i'll be very thankful to u if u'll help me getting some information.

Allium cepa

Mon Mar 30 2009

Old time gardeners almost always had a stand of potato onions in their gardens because they produced onions year round. For some odd reason, almost no one has them anymore.

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