How to Grow Onions

Green onions and scallions image by EwenAndDonabel/


Onions are part of the allium family, which makes it a cousin of garlic, shallots, chives and leeks. Onions can be grown from seeds, transplants or sets, with sets the most popular of the three. Being a cool-season vegetable permits the onion to be grown almost anywhere in the country. Onions can be classified as long-day (good for northern regions) and short-day (good for southern areas) and do best in the specified location. Onions are one of the most popular vegetables grown in gardens.

Step 1

Select a location to plant the onions that will provide at least six or more hours of full sun. Choose a site that has not been used for onions for the last three seasons.

Step 2

Provide enough space for 3 to 4 inches in between full-size (dry) onions and/or around 1 inch for green onions. Allow for a 1 to 1-1/2 foot space between rows.

Step 3

Prepare site as early as you can work the soil ahead of planting date. Planting should be done around the end of March or beginning of April.

Step 4

Use a rototiller, hoe and/or shovel to cultivate the soil thoroughly. Add compost and manure to the soil with a shovel and blend it in well. Smooth the soil with rake. Fertilizer can be added at this time, if needed.

Step 5

Purchase onion sets. Divide sets into two groups. Use ones smaller than a dime for growing dry onions and larger ones for growing green onions.

Step 6

Use a hand trowel or a gloved finger to make holes 1 to 1-1/2 inches deep. Place sets in holes with the pointy end up.

Step 7

Space plants according to type (green or dry) as previously described. Sets planted for green onions can actually touch. Press the soil firmly around the bulb.

Step 8

Supply a minimum of 1 inch of water per week. Use a drip or soaker hose for best results when rainfall is less than the amount needed.

Step 9

Mulch can be added to conserve water and help prevent weeds. Pull weeds by hand or carefully use a hoe to remove any weeds around growing onions.

Step 10

Harvest green onions when tops are 6 to 8 inches tall. Pull onions from the ground. Dry onions are ripe when between one-fourth to one-half of the top has fallen or you can wait until most all have fallen completely. Pull from the ground and allow to air dry.

Things You'll Need

  • Shovel
  • Gloves
  • Rototiller (optional)
  • Hoe
  • Rake
  • Organic aged compost or peat
  • Well-rotted manure
  • Trowel (optional)
  • Mulch
  • Fertilizer (10-10-10)
  • Water supply


  • University of Illinois Extension: Onion
  • University of Minnesota Extension: Growing Onions
  • Iowa State University: Growing Onions in the Home Garden

Who Can Help

  • Onion Gardening Tips: Planting Onions
  • Explore Cornell: Home Gardening Growing Guide: Onions
Keywords: grow onions, green onion, vegetable

About this Author

Diane Dilov-Schultheis has been writing professionally since 2000. She is a food and travel writer who also specializes in gaming, satellites, RV repair, gardening, finances and electronics. She is a member of the Society of Professional Journalists and has been published online at the Travel Channel and Intel.

Photo by: EwenAndDonabel/