Onions vary in size, shape, color, and flavor. The most common types are red, yellow, and white onions. The taste of these vegetables can range from sweet and juicy to sharp, spicy, and pungent, often depending on the season in which people grow and consume them. Farmers have cultivated allium vegetables for centuries. An onion is a round vegetable with a brown skin that grows underground. It has many white layers on its inside which have a strong, sharp smell and taste. Spring/summer onions, often referred to as fresh onions, include scallions, green onions, and spring onions. Spring onions are young onions and can be green, yellow or purple color. Spring onions have a white base that has not yet developed into a bulb.