How To Grow Onion Seeds

How To Grow Onion Seeds

Updated on Jan 25, 2022
By Shannon McCabe

The Allium family is comprised of onion, leeks, shallots, garlic, and chives, to name a few. Alliums are revered for their signature pungent fragrance and impressive medicinal properties. As if these delicious plants weren’t incredible enough, they are easy to grow and will also deter certain garden pests!

HISTORY

Wild onions are native to many parts of the world, but most of the domesticated onions we enjoy today are believed to have originated in Central Asia. In ancient Egypt, pharaohs were buried with onions as a symbol of eternity. European colonists brought onions to America, where they were surprised to find the natives using wild onions for food, as well as for medicine.

USES

  • Many culinary uses
  • Pest-repelling qualities

  • Start onion seeds indoors three months before the last frost date of spring.
  • Onions prefer cooler temperatures (60 F is ideal), and they will start out slowly.
  • Seeds germinate in 7-14 days.
  • Plant seeds ¼ inch deep.
  • Set out acclimated, stocky seedlings 4-6 weeks before the last frost of spring.

  • It is important to choose the right type of onion for your location; this will ensure that you have a successful crop that yields large bulbs.
  • Northern summers have drastically longer day length than locations farther south. Growers north of the latitude of Saint Louis, Missouri, should grow long-day varieties such as Ailsa Craig. Farther south, it is best to plant short-day varieties. Red Creole and Texas Early Grano are both perfectly suited for short days in the South. Some varieties are intermediate, or day neutral, and will form bulbs in any zone; however, they are especially suited for zones 5 and 6.
  • Plant onions in rich, moist, well-drained soil.
  • Space 6 inches apart in rows 12 inches apart.

PESTS/SPECIAL CONSIDERATIONS

  • Alliums do not tolerate competition from weeds, so be sure to mulch with straw or diligently keep up with weed pulling.
  • Consider interplanting onions with cabbage relatives; the sulfur from the onions may help deter pests.

  • Onions will cross with other onions, and occasionally they will cross with scallion types like Welsh onions and Hi Shi Ko bunching onions. Onions will never cross with leeks, chives or garlic.
  • If you are growing types that will cross, try to isolate varieties by at least several hundred feet or ideally up to one mile.
  • Onions are a biennial seed crop, so you will need to overwinter your first-year roots, ideally by digging them up and storing them for the winter. Replant in early spring, and allow onions to shoot up spikes of purple flowers.
  • Let seeds become dry on the plants. Pick seeds when they are hard and dark black, then bring them indoors to finish drying.
  • Once dry, separate the seeds from the husks or leave them on and plant them husks and all.