How to Store Onions

Cure properly for months of storage in cool, dry conditions

Quick Reference

Best temp: 45-55F (7-13C)
Humidity: 65-70% (dry!)
Storage life: 3-6 months
Curing time: 2-3 weeks

The Curing Process

Curing is essential for long-term onion storage. It dries the outer skins and seals the neck to prevent rot.

  1. 1
    Harvest at the right time

    Wait until tops fall over and begin to brown. Pull onions and let them dry in the sun for a day or two (if no rain).

  2. 2
    Set up a curing location

    Move to a warm (75-80F), dry, well-ventilated area out of direct sun. Garage, covered porch, or shed work well.

  3. 3
    Spread out in single layer

    Lay onions on screens, racks, or hang in bunches. Don't pile - air circulation is essential.

  4. 4
    Cure for 2-3 weeks

    Onions are ready when outer skins are papery, necks are tight and dry, and roots are dry and wiry.

  5. 5
    Trim for storage

    Cut tops to 1 inch (or leave for braiding). Cut roots close to bulb. Remove any loose outer skins.

Long-Term Storage Conditions

Temperature: 45-55F (7-13C)

Cool temperatures slow sprouting and decay. Basement, garage, or root cellar work well. Too warm causes sprouting; too cold (below 30F) causes freezing damage.

Humidity: 65-70% (Low!)

Onions need dry conditions - unlike most vegetables! High humidity causes mold and rot. This is why refrigerators (high humidity) don't work for onions.

Ventilation: Excellent Airflow

Good air circulation prevents moisture buildup and mold. Use mesh bags, hanging baskets, braids, or crates. Never store in sealed containers or plastic bags.

Storage by Onion Type

Long Storage (4-6 months)

  • • Yellow/brown storage onions
  • • Copra, Patterson, Cortland
  • • Thick-skinned varieties
  • • Low sugar content

Medium Storage (2-3 months)

  • • Red onions
  • • Spanish onions
  • • Shallots
  • • Most yellow varieties

Short Storage (1-2 months)

  • • Sweet onions (Vidalia, Walla Walla)
  • • Thin-skinned varieties
  • • High sugar/water content
  • • Use these first!

Use Immediately

  • • Green onions/scallions
  • • Damaged or bruised onions
  • • Thick-necked onions
  • • Any that didn't cure properly

Storage Methods

Mesh Bags

  • • Great airflow
  • • Easy to check for spoilage
  • • Hang or place in cool area
  • • Don't overfill - air needs to circulate

Braiding

  • • Traditional and decorative
  • • Leave tops long when curing
  • • Braid 8-12 onions together
  • • Hang in cool, dry location

Crates or Shelves

  • • Spread in single layer
  • • Good for large quantities
  • • Check regularly for spoilage
  • • Remove any bad ones immediately

Pantyhose Method

  • • Drop onion, tie knot, repeat
  • • Hang vertically
  • • Cut below knot when needed
  • • Quirky but effective!

Other Preservation Methods

Freezing

  • • Peel, chop, and freeze flat
  • • No blanching needed
  • • Becomes soft when thawed
  • • Best for cooking only
  • • Lasts 6-8 months

Dehydrating

  • • Slice thin or dice
  • • Dehydrate at 125-135F
  • • Takes 6-12 hours
  • • Store in airtight jars
  • • Lasts 1-2 years

Signs of Spoilage

  • Soft, mushy spots
  • Mold (black, white, or green)
  • Strong, foul smell
  • Excessive sprouting (interior becomes soft)
  • Slimy or wet outer layers

Small sprouts can be removed - onion is still usable if firm. Remove bad onions immediately to prevent spread to others.

Common Storage Mistakes

Skipping the curing processUncured onions rot within weeks; curing is essential
Storing in refrigeratorToo humid; causes soft rot and absorbs odors
Storing near potatoesBoth spoil faster together; keep in separate locations
Storing in plastic bagsTraps moisture and causes rot; use mesh or paper

Frequently Asked Questions

How long do onions last in storage?

Properly cured and stored onions last 3-6 months. Storage varieties (yellow, brown) last longest. Sweet onions only last 1-2 months. Red onions fall in between at 2-3 months.

Should onions be refrigerated?

No! Whole onions should be stored in a cool, dry, well-ventilated area at 45-55F. Refrigeration is too humid and causes soft rot. Only cut onions should be refrigerated, and used within 7-10 days.

What is curing and why is it important?

Curing is drying onions for 2-3 weeks after harvest. It dries the outer layers, closes the neck, and prepares onions for storage. Uncured onions will rot within weeks. Cured onions can last months.

Can you store onions with potatoes?

No! Both release gases and moisture that spoil each other faster. Store onions and potatoes in separate locations, preferably in different rooms or areas.

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