Onions are a popular vegetable with the home gardener because they have a wide variety of uses, are easy to grow, and require very little space. Additionally, they have a short growing season which means you can start harvesting in the spring, and then dry and store them for use in the winter. Onions are categorized into two growing types: long-day and short-day. Long-day onions are named such because they begin sprouting when the days between 14-16 hours in length (late spring/summer), while short-day onions begin sprouting when days are between 10-12 hours in length (winter/early spring).