For green or bunching onions, use sets or transplants in the spring. Sets and plants will be ready to eat in six to eight weeks. Thinnings of seed-grown bulb onions can also be eaten as green onions. Onions grown from sets do not make the best bulbs, and are rather costly. Avoid sets more than an inch in diameter, as they are likely bolt.
Late plantings are more susceptible to cold or freeze injury.
Planting too early can result in increased seed stem production. Seed is not a recommended method for growing onions in the Piedmont area of South Carolina. Sow eight to 12 seeds per foot of row to inches deep. If larger bulbs are desired, thin in spring to 4 inches apart and eat the thinned plants as green onions. Plants should be about 6 inches high and about half the thickness of a lead pencil at the time of transplanting.