The onion (Allium cepa) is the one of the most widely cultivated and popular plants, used as an essential ingredient in many recipes worldwide.
It is a hardy cool-season biennial with narrow hollow leaves and a base which enlarges to form a bulb.
The common onions are normally available in three colors:
Yellow onions are full-flavoured. They turn a rich, dark brown when cooked and give French onion soup its tangy sweet flavour.
Red onions are mild and a good choice for fresh uses like salads or in grilling and char-broiling.
White onions have a golden colour and sweet flavour and are the traditionally used in classic Mexican cuisine.
Onions are available in various forms - fresh, frozen, canned, caramelised, pickled, powdered, chopped, and dehydrated.
When, where and how to plant:
Onions can either be grown from seed or from seedlings started from seed the previous year. They can be bought as young plants from garden shops/nurseries to plant straight into garden beds.
You can choose your variety according to your climate and the time of year as some onions will grow better in the cooler months. Onions are ideal plants for growing in small confined spaces, and particularly thrive in raised beds.
Onion bulbs should sit on the surface of the soil and not covered. They start off looking like blades of grass.
Though onions prefer a sunny position with a rich but light soil, they will do well in most soils as long as it is firm.
You can grow them in seed trays, and plant out in 4-6 weeks. Seeds should be sown at a depth approximately three times the diameter of the seed. When planting, space plants 5-10 cm.
The seed trays don't have to be in a greenhouse, any sheltered spot will do. This is required for protection against rapid changes of temperature, especially at night.
Downy mildew, neck rot and white rot are the most common diseases that attack onions. To avoid these, plant disease-resistant varieties and keep the garden clean of debris. Diseased plants should be removed and disposed of immediately.
Onions six to eight months to mature. They are ready when the tops start to dry and fall over. Pull them and leave to dry for a few days. They should be stored in a cool, dry airy place.
How to use:
Onions are used in almost every type of food, including fresh salads and as a spicy garnish. Usually chopped or sliced, they are found in a large number of recipes in almost every culture around the world.
Depending on the variety, an onion can be sharp, spicy, tangy, pungent, mild or sweet. The whole plant is edible and is used as food in some form or the other.