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How to Grow Onions From Bulbs

By Barbara Raskauskas ; Updated September 21, 2017
Onions can be grown from bulbs.

Soup, salad, sauce, sandwich—there are many uses for onions, which are low in calories, and have no fat or cholesterol. Onion bulbs are produced by over-planting seeds. As the seeds grow, the crowded onions are unable to expand or gain needed soil nutrients, resulting in small bulbs that are suitable for planting the following season. The small bulbs are called sets. Gardeners will find that growing onions from sets is one way to add this flavorful, aromatic and sometimes tear-evoking vegetable to the family table.

Choose a sunny location to grow onions from bulbs. Use a shovel to till the soil for planting in the spring as soon as the soil is workable; this may be in March or early April. If planting a large garden, a rototiller may be used for tilling the soil.

Plant the onion bulb 1 inch deep by pulling the soil back with your fingers and pushing the blunt, fibrous end on the onion into the soil. Push the soil over the hole.

Plant subsequent onion bulbs about 3 inches apart in the row. Rows of onions should be spaced 12 to 18 inches apart.

Water after planting. Water as needed, which will be when the soil is dry 2 inches deep. The frequency of watering is dependent on the amount of rainfall, high temperatures and sunny days, but expect to water about every five days if there is no rainfall.

Apply a nitrogen-based fertilizer about three weeks after planting and then every two weeks until the beginning of July.

Harvest the onions when stems fall over, which may be in late July or early August. Vegetables have their highest moisture content in the morning, making mornings the best time to harvest. The onion can be pulled from the ground by the stem.


Things You Will Need

  • Onion bulbs
  • Shovel
  • Nitrogen-based fertilizer

About the Author


Barbara Raskauskas's favorite pursuits are home improvement, landscape design, organic gardening and blogging. Her Internet writing appears on SASS Magazine, AT&T and various other websites. Raskauskas is active in the small business she and her husband have owned since 2000 and is a former MS Office instructor.