How to Transplant Onion Sets

Dig once the soil is dry and workable in late winter to early spring soon after the last winter frost. Onions can tolerate a light frost, but not hard freezes. Break apart the clumps in the soil with a shovel and remove rocks, roots or other debris as you uncover them.

Apply a 2- to 4-inch layer of compost over the soil in the bed. Dig the bed, turning the soil over with your shovel, to mix in the compost. Drag the hoe through the soil to make 1-inch-deep planting furrows, spacing each row 12 to 18 inches apart.

Separate your sets into two bowls placing sets which are larger around than a dime into one bowl and sets that are smaller in width than a dime into the other bowl. The larger sets produce better green onions, while smaller onion sets grow well into large bulbs.

Plant your onions into your rows by pushing the wide end of the set down into the soil to cover about half its height. Cover over the planted sets with a light coating of soil to fill in each row. Plant the large sets so bulbs are almost touching to 1 inch apart. Plant the small sets 2 to 4 inches apart.

Water the area well to thoroughly moisten the soil and continue to deliver water at least twice a week, if not more often, when the garden receives less than 1 inch of rain per week. Hoe shallowly between rows as needed to keep the area weed free, handpicking where necessary.

Harvest green onions once the tops are 6 inches tall and pull up. Pull and use any bulb onions that form flower heads at the ends of stalks. Allow the remaining bulb onions’ plant material to turn brown, dry and die back on its own by fall. Pull the bulbs in the morning and allow to dry in the air for a day before trimming the plant portion off 1 to 2 inches above the bulb and storing.