Bunching onions, also known as Japanese bunching onions, Welsh onions, scallions or green onions, grow long and tubular, with white bottoms and green tops. Bunching onions do not form bulbs like other onions. All parts of the bunching onion--the white and greens--are edible. Grow bunching onions in a very sunny area for best results.
Select an area that receives at least 8 hours of sunlight each day. Bunching onions need as much sunlight as possible each day. Soil quality is not important. Bunching onions adapt to all qualities of soil, but cannot tolerate shady conditions.
Break up the soil with a spade or hand tiller. Till the soil at least 5 inches deep to enable the roots of the bunching onions to penetrate more easily.
Water the soil thoroughly, and allow excess water to drain away for an hour or two.
Sow bunching onion seeds on the surface of the soil. Space the seeds as evenly as possible, and sow a maximum of 25 seeds per square foot. Cover the seeds lightly with a dusting of dry potting soil.
Water every two to three days, unless the soil dries out sooner. The seeds will germinate within two weeks. Harvest time varies according to the type of bunching onion planted, but usually takes 56 to 119 days. Typical yield is 1 pound per square foot of planted seeds.