Onion

Onion (Allium cepa) is arguably the most essential vegetable in the kitchen, forming the flavor base for an enormous share of the world's savory cooking. Grown as an annual for its layered bulb, onion comes in short-day and long-day varieties tied closely to a region's latitude and day length.

Growing Onions

Onion bulb size is triggered by day length, so choosing the right type for your latitude matters more than almost any other factor — short-day varieties suit southern growers, while long-day varieties are needed farther north. Onions are shallow-rooted and need consistent moisture and weed-free soil, since they compete poorly with weeds for nutrients and water.

Culinary Uses

Onion's flavor transforms dramatically with cooking — sharp and pungent raw, but sweet and mellow after slow caramelization. Yellow onions are the reliable all-purpose choice for cooked dishes, while sweeter red and white onions are often preferred raw, in salads, salsas, and sandwiches, where their milder bite is an asset.