Summary
The common onion is a biennial bulb that is closely related to garlic, shallots and chives. Onions have hollow, tubular blue-green leaves that emerge from a bulb that is actually a modified leaf structure with many layers. A shallow network of roots extend from the bottom of the bulb, and the onion bulb itself may push partially above ground as the plant matures.
Description
The onion plant has a fan of hollow, bluish-green leaves and its bulb at the base of the plant begins to swell when a certain day-length is reached. The bulbs are composed of shortened, compressed, underground stems surrounded by fleshy modified scale (leaves) that envelop a central bud at the tip of the stem. In the autumn (or in spring, in the case of overwintering onions), the foliage dies down and the outer layers of the bulb become dry and brittle.
Additional Info
In colder climates, onion sets are usually planted in the spring when the weather is still cool but not frigid—above 28 degrees Fahrenheit. In warmer climates, onion sets are often planted in the fall, where they will remain dormant through the winter and begin growth in the spring. It takes about 3 1/2 months for the sets to mature into full-sized onions.
Varieties
Candy, Red, Scallions
