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Onion

Allium cepa

Vegetable

Onions are biennial crops grown as annuals, forming bulbs in response to day length. Their pungent scent deters many pests and makes them excellent companions for a wide range of vegetables.

Growing Conditions

Sunlight

Full Sun

Water Needs

Moderate

Soil

Rich, well-draining loam; pH 6.0–7.0

Spacing

4–6 inches

Days to Maturity

100–120 days from transplant; 60–80 days from sets

Growing Zones

1
2
3
4
5
6
7
8
9
10
11
12
13

Thrives in USDA Zones 3–10

Companion Planting

Good Companions

Keep Away From

When to Plant

  • Start Indoors

    10–12 weeks before last frost

  • Transplant

    4–6 weeks before last frost

  • Direct Sow

    Plant sets 4 weeks before last frost

  • Harvest

    When tops fall over naturally; cure 2–3 weeks before storage

Organic Growing Tips

  • Interplant with carrots — each deters the other's primary fly pest through aromatic confusion.

  • Mulch lightly to retain moisture without keeping soil overly wet, which promotes neck rot.

  • Cure bulbs thoroughly in a warm, airy place before storage to prevent rot.

  • Avoid overhead irrigation; use drip lines to keep foliage dry and reduce disease.

Common Pests

  • Onion Thrips
  • Onion Fly
  • Downy Mildew
  • Neck Rot

All pest management in Garden uses safe, organic, non-toxic methods only. No synthetic pesticides, ever.