Green onion

Green onions or scallions are really immature onions. Scallions are harvested while their tops are still green and before the bulb takes its full shape. Green onions can be eaten raw or cooked and have a milder flavor than their onion relative.

Selection
Purchase only green crisp tops and white bottoms. In general, the more slender bottoms will have a sweeter taste.

Storage
Scallions wilt within a couple days, so it’s best to use them immediately. However, if you must store them, refrigerate them in a tightly closed plastic bag up to one week.

Preparation
Rinse the scallions thoroughly as dirt may be lodged between the leaves. Trim any wilted parts and the tip of the white root. The entire scallion can be chopped or sliced and added to any of your recipes for added flavor.

Source

 * Vegetable of the Month: Leeks and Green Onions by the US Centers for Disease Control & Prevention, public domain government resource—original source of article