Last Updated on: February 12, 2026

How to Dry Onions for Storage

Knowing how to dry onions for storage (also called curing onions) is essential if you want your harvest to last for months. Even the best-grown onions won’t keep if they aren’t dried properly after lifting.

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Onions are a staple crop for gardens and allotments — easy to grow and brilliant for long-term storage when done right.

• Onion Sets (Spring & Autumn Planting)
Small starter bulbs that are quick and reliable to grow — ideal for beginners and perfect for strong, consistent harvests.
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Great if you want more choice, larger crops, or specific varieties for cooking or salads — cost-effective and ideal for early sowing under cover.
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Specially formulated fertiliser to support healthy leaf growth and strong bulb development — apply during the growing season for better yields.
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• Onion Storage Bags (Breathable Mesh Sacks)
Allows airflow while storing harvested onions — helps prevent rot and keeps bulbs fresh for months.
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• Onion Drying Rack / Harvest Storage Crate
Perfect for curing onions after lifting — improves longevity and ensures proper drying before storage.
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This guide explains the correct way to dry onions in the UK, how long it takes, where to do it, and common mistakes to avoid.

Why Drying Onions Properly Matters

Drying onions:

Seals the neck of the bulb
Toughens the outer skins
Reduces rot and mould
Extends storage life

Skipping or rushing this step is one of the main reasons onions spoil early.

For a full overview from planting to harvest, see ONION SETS UK: THE COMPLETE GUIDE TO PLANTING, GROWING & HARVESTING ONIONS.

When Should You Dry Onions?

Onions should be dried immediately after harvesting, once they are fully mature.

Only dry onions that:

Have yellowing leaves
Have tops that have fallen naturally
Feel firm

If you’re unsure about timing, see WHEN ARE ONIONS READY TO HARVEST IN THE UK.

How Long Do Onions Take to Dry?

In UK conditions, onions usually take:

2–3 weeks to dry properly

Drying time depends on:

Weather
Airflow
Bulb size
Where they’re dried

The onions are ready when the necks feel dry and papery.

Best Places to Dry Onions in the UK

Choose a location that is:

Dry
Well ventilated
Sheltered from rain
Out of direct, intense sunlight

Good options include:

A greenhouse with doors open
A shed with ventilation
A garage with airflow
Under cover outdoors in dry weather

Avoid damp rooms or sealed spaces.

How to Dry Onions (Step by Step)

Lift onions carefully and shake off loose soil
Leave leaves and roots attached
Lay onions out in a single layer
Ensure bulbs are not touching
Allow air to circulate freely
Turn onions occasionally

Never pile onions on top of each other while drying.

For correct lifting technique, see HOW TO HARVEST ONIONS PROPERLY.

Should You Wash Onions Before Drying?

No — onions should never be washed before drying.

Washing:

Traps moisture
Encourages rot
Slows the drying process

Simply brush off dry soil once onions are cured.

How to Tell When Onions Are Fully Dry

Onions are fully dried when:

Necks are completely dry
Outer skins are papery
Leaves are brittle
No moisture is felt at the base

Only fully dried onions should be stored long term.

When to Trim Leaves and Roots

Once onions are fully dry:

Trim leaves back to 2–3 cm
Remove roots if desired
Peel off loose outer skins

Avoid trimming too close to the bulb.

For storage guidance, see HOW TO STORE ONIONS LONG TERM.

What If the Weather Is Wet?

UK weather isn’t always ideal.

If it rains:

Move onions under cover immediately
Use a greenhouse, shed, or garage
Increase airflow with doors or vents

Keeping onions dry is more important than warmth.

Which Onions Shouldn’t Be Dried for Storage?

Do not store onions that are:

Damaged
Split
Bolted
Soft or bruised

These onions should be used quickly.

See WHAT TO DO WITH TOO MANY ONIONS for alternative uses.

Does Onion Type Affect Drying?

Yes.

Storage onions dry and store best
Red onions dry well but store slightly less time
Salad onions are best used fresh

For choosing the right onions to store, see BEST ONIONS FOR STORAGE IN THE UK.

Summary: How to Dry Onions for Storage

Dry onions immediately after harvest
Allow 2–3 weeks for proper drying
Use a dry, ventilated space
Don’t wash onions before drying
Store only fully cured bulbs

Drying onions properly is the key to enjoying your harvest well into winter.

For complete onion-growing guidance, return to ONION SETS UK: THE COMPLETE GUIDE TO PLANTING, GROWING & HARVESTING ONIONS.

Related Onion Growing Guides

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