Nothing is more disappointing than growing beautiful onions only to have them spoil a few weeks after harvest.

The secret to storing onions successfully isn’t just growing them well—it’s curing them properly.

Curing allows the outer layers to dry, the neck to seal, and excess moisture to leave the bulb. Done correctly, cured onions can last for several months, depending on the variety.

Whether you’re growing sweet onions like Texas Grano or storage varieties for winter use, here’s everything you need to know about curing onions.

What Does It Mean to Cure Onions?

Curing is the process of drying freshly harvested onions before putting them into storage.

During curing:

• The neck dries and seals.
• The outer skins become papery.
• Excess moisture leaves the bulb.
• Small wounds heal naturally.
• The onion becomes less likely to rot.

Think of curing as preparing the onion for its long winter rest.

Skipping this step greatly reduces storage life.

Why Curing Is So Important

Freshly harvested onions contain a lot of moisture.

Without curing, they are much more likely to develop:

• Mold
• Rot
• Soft spots
• Sprouting
• Short storage life

Taking two or three weeks to cure your onions can mean the difference between onions that last a few weeks and onions that stay fresh for months.

Harvest at the Right Time

Proper curing begins with harvesting onions at the correct stage.

Wait until:

• About 50–80% of the tops have naturally fallen over.
• The necks feel soft.
• The leaves begin yellowing.
• The bulbs have reached their expected size.

Avoid bending the tops over yourself. Let the plants finish naturally.

Choose a dry day whenever possible.

Handle Onions Carefully

Bruised onions don’t store well.

After harvesting:

• Lift bulbs gently with a garden fork or hand trowel.
• Brush off loose soil.
• Do not wash them.
• Leave the outer skins intact whenever possible.

Small cuts and bruises can become entry points for decay.

Choose the Right Place to Cure

The ideal curing location is:

• Warm
• Dry
• Shaded
• Well-ventilated

Good places include:

• Garage
• Covered porch
• Shed
• Barn
• Covered patio
• Open greenhouse with good airflow

Avoid curing onions in direct sunlight for long periods, especially during hot summer afternoons, as excessive heat can damage the bulbs.

Spread Them Out

Good airflow is essential.

Arrange onions:

• In a single layer
• On wire racks
• On screens
• On mesh shelves
• On newspaper (if kept dry)

Avoid stacking onions on top of one another.

Air should circulate around every bulb.

Leave the Tops Attached

Don’t trim the leaves immediately.

Keeping the tops attached allows moisture to continue leaving the bulb naturally during curing.

Once the neck is completely dry, you can trim the tops.

How Long Does Curing Take?

Most onions need:

2–3 weeks

Humidity plays a big role.

Dry weather speeds curing, while humid conditions may require additional time.

Patience is important—storing onions before they’re fully cured often leads to spoilage.

How to Tell When They’re Fully Cured

Your onions are ready for storage when:

• The neck is completely dry.
• The outer skin feels papery.
• The roots are dry and brittle.
• The bulbs feel firm.
• No green tissue remains in the neck.

If the neck still feels thick or moist, continue curing.

Trim the Onions

Once curing is complete:

• Trim roots close to the bulb.
• Cut the tops to about 1 inch above the bulb.

Some gardeners prefer braiding softneck onions instead of trimming them.

Both methods work well as long as the onions are fully cured.

Sort Before Storing

Not every onion belongs in long-term storage.

Set aside any onions that are:

• Bruised
• Cut
• Soft
• Split
• Diseased
• Thick-necked
• Bolted

Use these first in the kitchen.

Only healthy, fully cured onions should be stored for the long term.

Best Storage Conditions

Store cured onions in a place that is:

• Cool
• Dry
• Dark
• Well ventilated

Good storage containers include:

• Mesh bags
• Onion sacks
• Wire baskets
• Crates
• Open bins

Avoid:

• Plastic bags
• Airtight containers
• Damp basements
• Areas with poor airflow

Air circulation is just as important during storage as it is during curing.

Don’t Store Onions with Potatoes

Although they’re often displayed together at the grocery store, onions and potatoes shouldn’t be stored together at home.

Potatoes release moisture and ethylene gas, which can encourage onions to:

• Sprout sooner
• Soften
• Rot more quickly

Store them in separate locations whenever possible.

Which Onions Store the Longest?

Storage life varies by variety.

Excellent Storage Onions

• Patterson
• Copra
• Red Wing
• Yellow storage onions

These may last six months or longer under ideal conditions.

Medium Storage

• Candy
• Intermediate-day onions

Short Storage

Sweet onions such as:

• Texas Grano
• Vidalia
• Walla Walla

Because they contain more water and less sulfur, sweet onions typically don’t store as long. They’re best enjoyed within a few weeks to a few months after harvest.

Can Shallots Be Cured the Same Way?

Yes.

Shallots are cured exactly like onions.

Harvest them after the tops yellow and fall over naturally.

Then:

• Cure in a warm, airy location.
• Allow the necks to dry completely.
• Store in mesh bags or baskets.

Properly cured shallots can keep for several months.

Common Mistakes When Curing Onions

Avoid these common errors:

Washing the Bulbs

Extra moisture slows curing and increases the risk of rot.

Storing Too Soon

If the neck is still green or moist, continue curing.

Poor Airflow

Crowded onions trap moisture.

Always cure in a single layer with plenty of ventilation.

Direct Rain

Rain during curing can undo days of drying.

Move onions under cover if wet weather is expected.

Keeping Damaged Onions

One rotten onion can quickly affect nearby bulbs.

Always inspect onions before placing them into storage.

My Experience

One of my favorite onion harvests came from growing Texas Grano onions that I planted in the fall and protected with a frost cover over winter.

After harvesting them the following spring, I cured them in a dry, shaded area with plenty of airflow before storing them.

Although sweet onions like Texas Grano aren’t known for long storage, curing them properly still made a noticeable difference in how well they kept.

It’s a step I never skip because all the work of growing onions deserves the best chance of lasting as long as possible.

Final Thoughts

Growing onions takes patience, and curing them is the final step that rewards all your hard work.

Harvest them when the tops fall naturally, allow them to dry in a warm, well-ventilated place, and resist the temptation to rush them into storage.

A few weeks of curing can mean months of enjoying your homegrown onions.

Whether you’re growing sweet onions, storage onions, or shallots, proper curing helps preserve their flavor, improve their shelf life, and reduce waste—making every harvest even more rewarding.

Frequently Asked Questions

Can I cure onions outside?

Yes, as long as they’re protected from rain and direct afternoon sun. A covered porch or shaded patio with good airflow works well.

How long should onions cure?

Most onions cure in two to three weeks, though humid weather may extend the process.

Can I wash onions before curing?

No. Simply brush off loose soil. Washing adds moisture and increases the risk of spoilage.

What happens if I don’t cure onions?

Uncured onions are much more likely to rot, sprout, or develop mold during storage.

Which onions store the longest?

Long-day storage varieties such as Patterson, Copra, and Red Wing generally store much longer than sweet onions like Texas Grano or Vidalia.

Can I eat onions immediately after harvesting?

Absolutely. Fresh onions don’t need to be cured if you’ll use them right away. Curing is only necessary for long-term storage.

Related Articles

• How to Grow Onions
• When to Harvest Onions
• How to Grow Shallots
• When to Harvest and Cure Garlic
• How to Store Potatoes After Harvest
• Best Vegetables to Plant in Fall
• What to Do in Your Garden in August (Zone 7 Guide)
• How to Prepare Garden Beds for Fall Planting

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