Onions (Perennial) Growing Guide

Onions (Perennial)

Crop Rotation Group

Allium (Onion family) 

Soil

Any average, well drained soil.

Position

Full sun to partial afternoon shade.

Frost tolerant

Multiplying onions and other perennial strains are typically hardy to -26F (-15C) when given a protective winter mulch.

Feeding

Mix a balanced organic fertilizer into the soil before planting a new bed.

Companions

Potatoes, Lettuce, Beet, Thyme and Chives. Often grouped with garlic and shallots.

Spacing

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

Sow and Plant

Start with purchased bulblets or corms, set out 10 to 6 weeks before your first fall frost, or in early fall.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.

Notes

Most perennial onions grow vigorously in early spring and die back in midsummer. These interesting yet variable plants resemble shallots more than other onions.

Harvesting

Harvest bulblets from topsetting onions and use them as pearl onions in the kitchen. When plants die back, cured roots often yield a small shallot. In spring or fall, you can cut off small divisions for use as scallions (green onions).

Troubleshooting

In fall, move perennial onions to a fresh location to avoid problems with onion root maggots, which are attracted by decomposing onion tissues.

Planting and Harvesting Calendar

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