How to Cure and Store Onions To Last a Year

1. Understanding Onion Types and Storage Potential

Before diving into the curing and storage process, it’s important to know that not all onions store equally well. There are three main types:

• Short-day onions: These mature quickly and are best for warmer climates. They tend to be sweeter and have a higher water content, making them less suitable for long-term storage.

• Long-day onions: These are grown in cooler climates and are usually more pungent and better suited for storage.

• Intermediate-day onions: These fall between the two and have moderate storage ability.

For year-long storage, focus on growing and storing long-day or storage-specific varieties18.

2. Harvesting Onions at the Right Time

Timing your onion harvest is crucial for successful curing and storage:

• Signs of maturity: The tops (leaves) of the onions will start to yellow and fall over naturally. Once most of the tops have collapsed, stop watering and wait for 3–6 days to allow the bulbs to mature further and the necks to dry7.

• Harvesting: Choose a dry day. Gently loosen the soil around the bulbs and pull them out by hand. Avoid bruising or damaging the bulbs, as injuries can lead to rot during storage7.

3. Cleaning and Initial Sorting

• Do not wash onions: Moisture is the enemy of long-term storage. Instead, gently brush off excess soil with your hands or a soft brush57.

• Handle carefully: Any onions that are bruised, cut, or damaged should be set aside for immediate use, as they won’t store well8.

• Sort out doubles or split bulbs: These are more prone to spoilage and are best used fresh or preserved by freezing or canning1.

4. Curing Onions: The Essential Step

Curing is the process of drying onions so that their outer skins become papery and their necks seal, protecting the bulbs from moisture and pathogens. Proper curing is the secret to long-term storage.

How to Cure Onions

• Location: Cure onions in a dry, well-ventilated, and shaded area. Avoid direct sunlight, which can cause sunscald and uneven drying24568.

• Air circulation: Lay onions in a single layer on racks, screens, or mesh shelves. Alternatively, hang them in small bunches or braids. The goal is to maximize airflow around each bulb2568.

• Leave the leaves on: Keep the tops attached during curing. You can bend the necks over to help seal the bulbs and save space2.

• Duration: Cure onions for 2–4 weeks (sometimes up to 6 weeks for large or thick-necked varieties), until the necks are completely dry and tight, the roots are wiry, and the outer skins are crisp and papery23568.

Curing Tips

• Turn onions occasionally to ensure even drying.

• If rain threatens, move onions under cover immediately7.

• In very dry climates, onions can be cured in the field for a few days, but always finish curing in the shade to prevent sun damage45.

5. Trimming and Final Sorting

Once curing is complete:

• Trim roots and tops: Use sharp scissors to trim roots and cut tops to about 1 inch above the bulb. If you plan to braid onions for storage, leave the tops longer67.

• Final inspection: Discard any onions with soft spots, mold, or signs of sprouting. Use these immediately or preserve them by other means8.

6. Storing Onions for the Whole Year

Proper storage is just as important as curing. The right conditions will keep your onions fresh for months.

Ideal Storage Conditions

• Temperature: Store onions at 35–40°F (1–4°C)—the coldest spot in your home that won’t freeze, such as a basement, root cellar, or unheated garage278.

• Humidity: Onions prefer low humidity to prevent sprouting and rot. Avoid damp basements or refrigerators unless you’re storing sweet or short-day onions, which don’t store as long279.

• Darkness: Store onions in a dark place to prevent sprouting27.

• Air circulation: Use mesh bags, crates, baskets, or hang onions in braids to allow airflow around each bulb. Never store onions in plastic bags, which trap moisture and cause rot3789.

Storage Methods

• Mesh bags: Hang mesh bags from hooks or rafters.

• Open crates or baskets: Stack onions in shallow layers to avoid crushing.

• Braids: Braid onions with their tops and hang them in a cool, dry spot.

• Stackable baskets: For large harvests, stackable baskets with good airflow are effective9.

Special Notes for Sweet and Short-Day Onions

• Sweet onions and short-day varieties have higher water content and thinner skins. Cure them briefly (a few days), then refrigerate and use them within a few weeks to months1.

7. Monitoring and Maintenance

• Check regularly: Inspect your stored onions every few weeks. Remove any that are soft, sprouting, or developing a foul odor to prevent spoilage from spreading8.

• Expect some loss: Even with perfect curing and storage, some onions may not last the full year. Use storage onions first, and plan to grow enough to account for some natural attrition.

8. Alternative Preservation Methods

If you have more onions than you can store, consider:

• Freezing: Chop and freeze onions for later use in cooked dishes.

• Dehydrating: Slice and dry onions for homemade onion flakes or powder.

• Pickling or canning: Preserve onions in vinegar or as part of relishes.

9. Common Mistakes to Avoid

• Washing onions before curing: Moisture encourages rot.

• Curing in direct sun: Leads to sunscald and uneven drying.

• Storing in plastic: Traps moisture and promotes decay.

• Storing damaged onions: Use these immediately.

• Ignoring regular checks: One spoiled onion can ruin a batch.

10. Frequently Asked Questions

Q: Can I eat onions right after harvest?
A: Absolutely! Fresh onions are delicious, but they won’t keep long unless cured78.

Q: How long will properly cured and stored onions last?
A: Storage varieties can last 9–12 months. Sweet and short-day onions last a few weeks to a few months38.

Q: What if my onions start sprouting?
A: Use sprouting onions immediately. Sprouting is often a sign of storage temperatures that are too warm or too humid.

Q: Why do some onions rot in storage?
A: Rot is usually due to incomplete curing, high humidity, or storing damaged bulbs.

Conclusion

Curing and storing onions is a simple but essential process for any gardener or homesteader who wants to enjoy their harvest all year long. By harvesting at the right time, curing thoroughly in a dry, shaded, and well-ventilated space, trimming and sorting carefully, and storing in cool, dark, and airy conditions, you can keep onions fresh for up to a year. Regular checks and proper handling will minimize losses and ensure you have a steady supply of flavorful onions for every season.

Start planning your onion harvest and storage now, and you’ll be rewarded with homegrown onions in your kitchen all year round!

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