Bulb onion
Allium cepa

Family: Amaryllidaceae

What it is like

An onion family plant. A herb with a two year life cycle. Normally it develops fattened bulbs at the base. It has a shallow fibrous root system. The actual stem in very short and condensed. Leaves are produced in an alternate fashion one after the other from the top of this stem. Successive leaves grow up inside, then burst through the leaf sheath of the previous leaf. Leaves are thin and long. They are slightly to markedly flattened on the upper surface. Long day lengths and warm temperatures help the leaf bases become swollen and store food reserves. Flowers are greenish white in colour. Flowers develop on a rounded head with stalks all coming from the centre. Flowers in the rounded head open irregularly. There are no bulbils on the flower-head. There are short day cultivars that will form bulbs in the tropics.

There are about 300-700 Allium species. Most species of Allium are edible (Flora of China). All alliums are edible but they may not all be worth eating! They have also been put in the family Alliaceae.

Where it is found

A temperate plant. It is more easy to get onions to grow and form bulbs in the highlands in the tropics but they can be grown from sea level to 2600 m altitude in Papua New Guinea. In Nepal they grow to 3000 m altitude. They do not suit the wet humid tropics. Because the day lengths are short near the equator, onions often do not produce a bulb. Some newer varieties will yield in the tropics. It plant grows best at 12-21°C and the bulb forms best at 15-25°C. It grows best with a pH 5.7-6.6. It suits hardiness zones 5-10.

Countries/locations it is found in

Afghanistan, Africa, Albania, Amazon, Andorra, Angola, Argentina, Armenia, Asia, Australia, Austria, Azerbaijan, Balkans, Bangladesh, Benin, Bolivia, Brazil, Britain, Brunei, Burkina Faso, Cambodia, Canada, Cape Verde, Caucasus, Central Africa, Central America, Central Asia, China, Colombia, Congo, Cook Islands, Costa Rica, Côte d'Ivoire, Cuba, East Africa, East Timor, Ecuador, Egypt, Europe, Fiji, Finland, FSM, Gabon, Georgia, Ghana, Greece, Guam, Guyana, Haiti, Hawaii, Himalayas, India, Indochina, Indonesia, Iran, Iraq, Ireland, Italy, Ivory Coast, Jamaica, Japan, Jordan, Kazakhstan, Kenya, Korea, Kyrgyzstan, Lithuania, Macedonia, Madagascar, Malawi, Malaysia, Marshall Islands, Mediterranean, Mexico, Micronesia, Middle East, Moldova, Myanmar, Nauru, Nepal, Netherlands, Nicaragua, Niger, Nigeria, North Africa, North America, Northeastern India, Pacific, Pakistan, Papua New Guinea, Peru, Philippines, Pohnpei, Poland, Romania, Russia, Sahel, Saudi Arabia, Scandinavia, SE Asia, Senegal, Serbia, Sikkim, Slovenia, Somalia, South Africa, Southern Africa, South America, South Korea, Spain, Sri Lanka, Sudan, Switzerland, Tajikistan, Tanzania, Tasmania, Thailand, Timor-Leste, Tonga, Turkey, Türkiye, Uganda, Ukraine, Uruguay, USA, Uzbekistan, Vanuatu, Vietnam, West Africa, West Indies, Zambia, Zimbabwe

How it is used for food

The bulbs and leaves are used as flavouring raw or cooked. The flowers are crushed and eaten.

In Papua New Guinea, it is not widely grown but is popular and imported for sale. It is a commercially cultivated vegetable.

Edible parts

Leaves, bulbs, seeds, herb, spice, vegetable, flowers

How it is grown

They are grown from imported seed. For bulbs, a tropical cultivar is needed and bulbing is normally better at higher altitudes. Cultivars which form flowers early need to be avoided. Seedlings can be transplanted.

Its other names

Local names

Albasa, Anyezi, Basal, Bawang, Besalim, Butungulu, Cebola, Cebolla, Cebula, Chivannaulli, Cibule, Cipolla, Dungari, Irulli, Kanda, Kuchen zweibel, Kywtthun-ni, Luk, Mangafaka, Nirulli, Oignon, Palandu, Piaja, Piyaz, Pyaj, Pyanj, Pyaz, Sogan, Sybo, Talap, Tamanegi, Tongolobe, Tschong, Ulligaddalu, Ullikadalu, Vengayam, Yang cong, Yangpa

Synonyms

Allium angolense Baker; Allium aobanum Araki; and others