How to Plant an Onion & Care For It


Onions are an easy to grow addition to your summer vegetable garden. Purchase onion sets, which are small seed onions, from a local nursery or garden center instead of a mail order company to ensure the variety is suited to your climate. Onions can also be planted from seed, but they may not mature to full size bulbs in time for harvest. Planting and caring for the onion sets properly ensures a bountiful harvest of large, full bulbs.


Step 1

Lay a two inch layer of compost over a garden bed that receives full sun. Choose a well-drained bed that isn't prone to standing water. Till the compost into the soil to a 10 inch depth to add nutrients to the soil.

Step 2

Plant onion sets in spring as soon as the soil thaws enough to be worked. Plant a single set one inch deep and space them four inches apart in rows. Space the rows 12 to 18 inches apart.

Step 3

Water the freshly planted onions with one cup of a starter fertilizer solution, mixed according to package instructions.


Step 1

Water the onion plants once a week, providing about one inch of water to the bed at each watering. Water more often during dry periods if the soil begins to feel dry.

Step 2

Weed between the onion plants with a hand cultivator. Use the cultivator to break up the top two inches of soil which inhibits weed seed germination.

Step 3

Fertilizer the plants with a general purpose fertilizer approximately six weeks after planting. Follow label instructions for exact application amounts.

Step 4

Harvest the onions when the foliage yellows and falls over. Loosen the soil around the bulb with a spade then pull the onion out of the soil by its dead foliage. Cut the foliage down to one inch high. Store harvested onions in a cool, dry place until ready to use.

Tips and Warnings

  • If the weather is too warm the onion may send up a flower stalk prematurely. Dig up these bulbs and use immediately, or they will quickly begin rotting.

Things You'll Need

  • Compost
  • Starter fertilizer
  • Hand cultivator
  • General fertilizer


  • University of Illinois Extension: Onion
Keywords: planting onions, onion plant care, root vegetable

About this Author

Jenny Harrington has been a freelance writer since 2006. Her published articles have appeared in various print and online publications, including the "Dollar Stretcher." Previously, she owned her own business, selling handmade items online, wholesale and at crafts fairs. Harrington's specialties include small business information, crafting, decorating and gardening.