The Yellow Sweet Spanish onion is one of the most popular long-day varieties for both home gardeners and market growers. The large bulbs can grow upwards of a pound a piece, and have a mild, sweet taste. These onions are great for fresh eating or for cooking, and if cured properly, can be stored for up to six months. Can’t wait four months for your onion harvest? Simply pull them at any age for great tasting green onions!