Vidalia onions are grown over a long season. Growers begin growing transplants in the fall and aren't finished with the crop until late spring the following year.
If you didn't start your seed last fall, don't worry. Transplants are available. Local feed-and-seed, building-supply and department stores are sources. Transplants are typically dug and sold bare-root in bundles.
Most commercial growers will transplant their onions between Thanksgiving and Christmas. Weather and other factors can delay their planting, though. It isn't unusual for growers to still be planting in January and even into February.
Purchased transplants can be planted in January and February without any problems. But because it is somewhat later than the usual planting date, the onions may be smaller than expected at harvest.
Be sure to select only locally grown onions. Onion seeds, sets or transplants from catalogs may not be Vidalia types.
Onions are day-length sensitive, and onions for this part of the country are called short-day onions. This means that during the short days of winter, these onions will form bulbs. Onions grown elsewhere are called long-day onions because they form bulbs during summer.
When choosing transplants, select only bundles that look fresh and green and have no dead leaves. These bundles should be kept moist in the store and when you bring them home until planting. However, overly wet onions can develop disease problems and should be avoided.
Prepare your garden well in advance. Apply fertilizer, and work it into the soil. Onions are heavy feeders, so get a soil test to determine the right amount of fertilizer to use. Your county extension office can handle this for you.
The tops of your transplants may have been clipped when pulled and bundled. If not, clip them yourself to a length of 3 to 5 inches before planting.
Plant the onions 1 to 2 inches deep with 4 to 5 inches between each transplant in the row. Rows can be spaced 12 to 14 inches apart.
Keep an eye on them. Pay particular attention to watering, especially during the first two weeks after transplanting.
(George Boyhan is a Cooperative Extension horticulturist with the University of Georgia College of Agricultural and Environmental Sciences)