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Onion roots in the soil

Onion

October 2024 | Written by: New Castle County Master Gardeners Rick Judd and Gail Hermenaus

 

General information

  • Scientific Name: Allium cepa
    • Family: Alliaceae, Amaryllidaceae
  • Cool season
  • Planting Window: mid-March to mid-April
  • pH = 5.5-7.0
  • Planting Depth:
    • Seeds: 1/2 inch, direct sow in soil
    • Sets: lay in hole, roots down, cover with soil half way up the bulb
  • MPD: 3 inches (in both directions)
  • Can be companion planted with cabbage family members, beets, tomatoes and lettuce
  • Tip: onions like rich, composted soil!

Pests and diseases

  • Onion maggot - use floating row covers to prevent flies from infesting plants

Successful cultivars and harvest

  • Cultivars:
    • Seeds: White Lisbon Bunching (60 days)
    • Sets: available sets Stuttgarter
  • To harvest, pull from ground when tops are brown
  • Harvest green onions mid-May through late June; harvest large onions late July through late August
  • If storing onions, allow tops to wilt, cut off 1-2 inches above bulb and dry for one week
Onion photos courtesy of Gail Hermenau.
Onion photos courtesy of Gail Hermenau.
Onion photos courtesy of Gail Hermenau.

This publication was created by Master Gardener Rick Judd and designed by Extension Scholar Taylor Trent. Photos courtesy of Rick Judd.


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