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Allium cepa - L.

Common Name Onion, Garden onion
Family Alliaceae
USDA hardiness 4-8
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]. Hand eczema may occur with frequent handling. May interfere with drug control of blood sugar [301].
Habitats Not known in the wild.
Range W. Asia - Iran? The original habitat is obscure.
Edibility Rating    (5 of 5)
Other Uses    (0 of 5)
Weed Potential No
Medicinal Rating    (3 of 5)
Care
Fully Hardy Moist Soil Full sun
Allium cepa Onion, Garden onion


Allium cepa Onion, Garden onion

 

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Summary


Physical Characteristics

 icon of manicon of bulb
Allium cepa is an evergreen Bulb growing to 0.6 m (2ft).
It is hardy to zone (UK) 5 and is not frost tender. It is in flower from June to July. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, insects.
Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: acid, neutral and basic (alkaline) soils and can grow in very alkaline soils.
It cannot grow in the shade. It prefers moist soil.

Synonyms

Allium angolense, Allium aobanum, Allium ascalonicum, Cepa esculenta

Habitats

 Cultivated Beds;

Edible Uses

Edible Parts: Flowers;  Leaves;  Root;  Seed.
Edible Uses:

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].

Composition
Figures in grams (g) or miligrams (mg) per 100g of food.
Root (Fresh weight)
  • 72 Calories per 100g
  • Water : 79.8%
  • Protein: 2.5g; Fat: 0.1g; Carbohydrate: 16.8g; Fibre: 0.7g; Ash: 0.8g;
  • Minerals - Calcium: 37mg; Phosphorus: 60mg; Iron: 1.2mg; Magnesium: 0mg; Sodium: 12mg; Potassium: 334mg; Zinc: 0mg;
  • Vitamins - A: 0mg; Thiamine (B1): 0.06mg; Riboflavin (B2): 0.02mg; Niacin: 0.2mg; B6: 0mg; C: 8mg;
  • Reference: [ 218]
  • Notes:

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;  Appetizer;  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]. The German Commission E Monographs, a therapeutic guide to herbal medicine, approve Allium cepa Onion for appetite loss, arteriosclerosis, dyspeptic complaints, fevers & colds, cough/bronchitis, hypertension, tendency to infection, inflammation of mouth and pharynx, common cold (see [302] for critics of commission E).

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.

Other Names

If available other names are mentioned here

Found In

Countries where the plant has been found are listed here if the information is available

Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

Conservation Status

IUCN Red List of Threatened Plants Status :

Related Plants
Latin NameCommon NameEdibility RatingMedicinal Rating
Allium acuminatumHooker's Onion, Tapertip onion32
Allium aflatunensePersian Onion, Ornamental Onion22
Allium akaka 32
Allium altaicum 32
Allium ampeloprasumWild Leek, Broadleaf wild leek53
Allium ampeloprasum babingtoniiBabington's Leek33
Allium angulare 32
Allium angulosumMouse Garlic32
Allium atropurpureum 32
Allium bisceptrumAspen Onion, Twincrest onion32
Allium bodeanum 32
Allium bolanderiBolander's Onion32
Allium brevistylumShortstyle Onion32
Allium canadenseCanadian Garlic, Meadow garlic, Fraser meadow garlic, Hyacinth meadow garlic42
Allium canadense mobilenseCanadian Garlic52
Allium carinatumKeeled Garlic32
Allium carolinianum 32
Allium cepa aggregatumPotato Onion43
Allium cepa ascalonicumShallot53
Allium cepa proliferumTree Onion53
Allium cernuumNodding Onion, New Mexican nodding onion52
Allium chinenseRakkyo42
Allium condensatum 32
Allium cupanii 32
Allium douglasiiDouglas' Onion32
Allium dregeanumWild Onion32
Allium drummondiiPrairie Onion, Drummond's onion32
Allium fistulosumWelsh Onion52
Allium flavumSmall Yellow Onion, Ornamental Onion22
123

 

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Expert comment

Author

L.

Botanical References

200

Links / References

For a list of references used on this page please go here

Readers comment

miranda   Wed May 10 2006

a physical plant description would be much appreciated.

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.

Mark Moodie   Wed Oct 18 2006

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

Vishvas   Wed Jan 17 2007

Its good effort . But update with some more links

National Research Centr For Onion & Garlic

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

muh'd salisu   Thu Jan 25 2007

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

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 ??

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.

   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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