Onion Growing Guide

Allium cepa

Crop Rotation Group

Allium (Onion family) ●

Soil

Fertile, well-drained soil enriched with compost.

Position

Full sun.

Frost tolerant

Yes.

Feeding

Mulch with compost before planting your onions. Do not feed plants that are nearing maturity if you want very sweet onions.

Spacing

Single Plants: 5" (15cm) each way (minimum)
Rows: 3" (10cm) with 7" (20cm) row gap (minimum)

Sow and Plant

Start seeds in pots under cover in late winter before planting out in spring, or grow from purchased sets (immature bulbs) planted in spring.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.

Notes

Onions respond to changing day length. Grow short-day varieties in southern latitudes. Long-day varieties work best in northern areas. Try growing different varieties from seed to explore differences in bulb color, size and shape.

Harvesting

Harvest young onions as scallions. When bulbs form and the tops of the plants fall over, pull them and cure in a warm place for about 10 days before storing.

Planting and Harvesting Calendar

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Pests which Affect Onion

Aphids (General)

Onion Root Maggot

Slug

Snail

Plant Diseases which Affect Onion

Allium White Rot

Onion Downy Mildew

Onion Fusarium Basal Rot

Onion Pink Root