Onions of various size, color, and pungency are used in cuisines worldwide. Common types include yellow or brown onion (e.g. Spanish onions), sweet onion (e.g. Vidalia onions), white onion, red onion, and shallots.
Buy onions that are firm with tight, dry skin and store them in a cool, dark place, but not with your potatoes! The potatoes release ethylene gas and moisture, both of which will make your onions go bad faster.
Most onions are available everywhere and during all seasons.1 Green onions (a.k.a. scallions) and spring onions are two similar types of immature onions with a less intense onion flavor. They are in season in spring and summer.
Confusingly, the terms "green onion", "scallion", and "spring onion" are often used interchangeably and are often used differently in the US, UK, and Australia. That said, spring onions are generally thought to have a round white bulb at the bottom, while green onions/scallions have a straight white bottom. Whichever type you choose, purchase spring onions/green onions with fresh green tops and firm white bottoms and store in the refrigerator with the bottoms in a glass of water.
The nutrition DNA of onions. For example, you can see that 1 onion covers 16% of your daily allowance of sugar and 10% of the recommended Vitamin C intake. Hover over the bars to see which nutrient is covered.