Onions are among the world’s oldest cultivated plants. They were probably known in India, China, and the Middle East before recorded history
In Egypt, onions can be traced back to 3500 B.C. There is evidence that the Sumerians were growing onions as early as 2500 B.C. One Sumerian text dated to about 2500 B.C. tells of someone plowing over the city governor's onion patch. Onions are grown by smallholder farming in most countries and are identified with traditional medicine (e.g. as a diuretic). In the tropics, onions can be grown year-round where irrigation is possible.
The history of onion farming in Africa is long and varied. Onions are believed to have been first domesticated in Central Asia, and they were introduced to Africa by traders and explorers over 2,000 years ago. Onions quickly became a popular crop in Africa, and they are now grown in many different countries across the continent.
Onion farming in Africa has played an important role in the region's economy. Onions are a major source of income for many farmers, and they are also an important source of food for people across Africa. Onions are a versatile crop that can be used in a variety of dishes, and they are also a good source of vitamins and minerals.
Maturity Duration: 3 - 5 months after transplanting
Expected Yield: Up to 17 tons per hectare
Growing Season per Year: Twice on rain-fed and thrice under irrigation.
Nutritional Value: Per 100 g / % Daily Values. 30 g calcium, 0.5 mg of iron, vitamin B, 0.2 mg of riboflavin, 0.3 mg nicotinamide, and 10 mg ascorbic acid (vitamin C)
Altitude: 0 – 2,000 meters above sea level
Rainfall: Over 600 mm of rainfall annually
Temperature: 13 and 24°C in temperate and 15-30°C in tropics
Soils: Fertile, well-drained, non-crusting soil
PH: 6.0 – 6.8
There are a number of commercial varieties of onions available:
Globe-shaped onions may be white, yellow, or red. They have strong flavour and are used chiefly for soups, stews, and other prepared dishes and for frying.
- Bermuda onions are large and flat, with white or yellow colour and fairly mild taste. They are often cooked and may be stuffed, roasted, or french-fried. They are also sliced and used raw in salads and sandwiches.
- Spanish onions are large, sweet, and juicy, with colour ranging from yellow to red. Their flavour is mild, and they are used raw and sliced for salads and sandwiches and as a garnish.
- Italian onions, or cipollini onions, are flat and are red, white, or yellow in colour and often have a mild, sweet flavour. They are used raw for salads and sandwiches, and their outer rings make an attractive garnish.
- Shallots are a small, angular variety of onion. They are typically white with a brown or red skin and have a mild flavour. The green leaves can also be eaten.
- Pearl onions are not a specific variety but are small round onions harvested when 25 mm (1 inch) or less in diameter. They are usually white and pickled and used as a garnish and in cocktails.
- Spring onions are small white onions that are picked when between 25 and 38 mm (1 and 1.5 inches) in diameter; the tops are sometimes left attached. They are used to flavour foods having fairly delicate taste, such as omelets and other egg dishes, sauces, and peas. They are also served boiled or baked.
- Green onions, also called scallions, are young onions harvested when their tops are green and the underdeveloped bulbs are 13 mm (0.5 inch) or less in diameter. Their flavour is mild, and almost the entire onion, including top, stem, and bulb, is used raw in salads and sauces, as a garnish, and as a seasoning for prepared dishes.