SafePlants

Onion (Allium cepa)

The term "onion" refers to a variety of Allium cepa, including bulbing onions, scallions, and shallots. They are widely cultivated and consumed globally.

Considerations for Pets

• Onions, particularly the bulbs, can cause toxicity in pets.
• The presence of organosulfides and sulfoxides, which are found in onions, can damage red blood cells.

Considerations for Children

• Onions are commonly grown in home gardens and allotments, making children potentially exposed to them.

Taxonomy and Nomenclature

• Scientific Name: Allium cepa
• Family: Alliaceae
• Variety: Allium cepa var. cepa (referring to scallions, bunching onions, and green onions)

Common Names

• Onion
• Scallions
• Bunching Onions
• Green Onions

Distribution and Habitat

• Research suggests onions were first grown in Iran and West Pakistan.
• Varieties like Texas Early Grano were developed at the Texas Agricultural Experiment Station of Texas A&M.

Morphological Characteristics and Growth Habits

• Bulb shape varies depending on the variety (e.g., round, globe-shaped, blocky).
• Skin color varies (e.g., yellow, red, white).
• Some varieties are known for their high-quality skin, making them suitable for storage.
• The size of the onion bulb is dependent on the number and size of the green leaves.

Cultivation and Uses

• Onions can be grown from seeds or sets (small bulbs).
• Sowing times vary:
  • Indoors in trays as early as January.
  • Direct sowing from early- to mid-spring.
• Planting distance: Onions 5-10cm (2-4ins), shallots 15-20cm (6-8in) apart.
• Onions are used in various meals and store well, often until the following spring.
• They are harvested at different times depending on the variety (e.g., early summer for autumn-planted sets, mid-April to May for Early slug (Babosa) Onion, early January to early March).
• Some varieties are suitable for medium-term storage.
• Onions are planted early in the spring in cooler climates for optimal bulb growth.

Varieties

• T&M's First Early: An overwintering onion that produces attractive bulbs.
• Unwins First Early: An early-maturing variety with yellow skin and a uniform, round shape.
• Red Baron: A reliable and tasty red onion that matures early and is resistant to fungal problems.
• Texas Early Grano: Known for ease of growing, flavor, and disease resistance; also called "The Mother of All Sweet Onions."
• New York Early: An early and dependable yellow onion selected to store until spring.
• Early Barletta: An onion variety.
• Texas Early Grano 502 PRR: A "Vidalia-type" onion.
• Early slug (Babosa) Onion: A variety harvested from mid-April to May, with a slightly spicy flavor.
• Hyred: An F1 hybrid red onion.