How to Plant & Grow Onions


Onions are one of earliest vegetable crops to emerge in the spring and, because of the relative ease to grow them, they are a favorite among gardeners. Being frost resistant also makes onions a hardy vegetable that can stay in the ground year-round. Used onions raw or cooked in many culinary dishes and to top those summer burgers.


Step 1

Plant your onions from mid to late March after the last frost. Choose an area that receives full sun daily and has well-draining soil.

Step 2

Prepare the garden area as soon as the ground is workable by tilling the soil and working in compost or manure. This adds needed nutrients and makes the soil well-draining, which is vital for onions.

Step 3

Dig a hole twice as deep as the root ball and space the plants 4 inches apart. If planting rows of onions, keep the rows about 6 inches apart to allow room for the plants to grow without crowding each other out.

Step 4

Place the plants deeply in the holes so just the neck is showing above the ground. Fill in with soil and firm the top over with your hand. Water deeply after planting to help establish the roots.


Step 1

Water your onion plants consistently so the soil stays moist but not soggy. Give the plants about 1 inch of water weekly and use a soaker hose for deeper water. Soak the soil for about one hour each week. Let the soil dry out once the tops of the onions start to yellow and fall over.

Step 2

Fertilize once a month in late May and again in June with a high nitrogen fertilizer (e.g. 21-0-0) to provide the needed nutrients to grow healthy foliage and roots. Do not fertilize after late July to allow the plants to start dying back and getting ready for harvest.

Step 3

Apply mulch around the plants to retain moisture and control weeds. Use an organic mulch such as grass clippings and leaves. Pull any weeds, especially in the first two months when the roots are getting established. In the late fall before the first frost, apply 2 to 4 inches of mulch to help the plants winter over.

Tips and Warnings

  • Do not let harvested onions get wet.

Things You'll Need

  • Compost
  • Fertilizer
  • Mulch


  • Gardening Know How; How to Grow Onions in Your Garden
  • Gardening Patch; How to Grow Onions
  • Utah State University Extension; Onions in the Garden
Keywords: plant grow onions, planting onions, growing onions

About this Author

Residing in Southern Oregon, Amy Madtson has been writing for Demand Studios since 2008 with a focus on health, pregnancy, crafts and gardening. Her work has been published on websites such as eHow and Garden Guides, among others. Madtson has been a childbirth educator and doula since 1993.