Permapotes
Onions

White onion

White onion: Sowing, planting and harvest calendar

White onion is a form of Allium cepa, in the Amaryllidaceae family. It has white or very pale outer coverings and white flesh arranged in layers. This colour distinguishes it visually from yellow and red onions without making it a separate species. The name includes several cultivars with differently shaped and sized bulbs, as well as uses involving young onions or more mature bulbs.

The bulb consists of thickened leaf bases arranged around a centre. Fleshy inner layers form a store of reserves, while the outer coverings become drier as the bulb matures. Above it, elongated, hollow green leaves give the plant an upright outline. A young onion with green foliage therefore looks different from a mature bulb with dry outer skins, even when both belong to the same cultivar. These are different stages of the same plant’s development.

Many white onions are enjoyed as small fresh onions with a pale lower part and leaves that are still green. Other uses involve more developed bulbs. ‘White Lisbon’ is one example of a salad onion belonging to Allium cepa. However, the terms spring onion and salad onion do not always identify that species: some leafy onions used in similar ways belong to Allium fistulosum. Culinary names therefore do not establish the complete botanical relationship between plants.

The flavour combines an onion aroma, pungency and a variable degree of sweetness. White skin does not guarantee an identical taste across all cultivars. Raw onion brings crunch to salads, garnishes and cold preparations. Cooked, you can find it in soups, sauces, sautéed dishes, savoury tarts and stews. The leaves of young onions also contribute a green, aromatic element to a dish, with a different appearance from slices of a whole mature bulb.

The onion generally has a biennial life cycle, although it is commonly grown for its bulb within one cropping season. Flowering belongs to its reproductive phase, distinct from bulb formation alone. In the vegetable garden, white onions extend the diversity of bulb onions through pale colouring and different stages of culinary use. Storage suitability depends on cultivar and maturity: a small fresh onion and a dry mature bulb are not interchangeable products.

White onion
White onion
Characteristics
  • Lifecycle : Annual
  • Exposure : Full Sun
  • Frost Hardiness : Frost Resistant
  • Cultivation Difficulty : Easy
  • Mature height : 30 cm
Sowing & Planting
  • Greenhouse Growing : Not Required
  • Sowing Depth : 2 cm
  • Plant Spacing : 10 cm
  • Row Spacing : 20 cm
Maintenance
  • Maintenance : Low
  • Water Requirements : Moderate
Other characteristics
  • Soil Type : Humus-rich
  • Soil pH Preference : Neutral
  • Pest Sensitivity : Moderate
  • Disease Sensitivity : Moderate
  • Weed Sensitivity : Moderate
  • Pollination : Insect-pollinated
  • Propagation : Sowing