Curing Onions, Garlic, Potatoes and Winter Squash
Some vegetables can be eaten as soon as they are harvested but need further preparation if they are to remain in good condition for several months.
Curing is a controlled period of drying or resting that allows protective skins to harden, excess surface moisture to disappear and minor harvesting injuries to heal. It is especially important for onions, garlic, potatoes and winter squash.
These crops are often described together, but they must not all be cured in the same way. Onions and garlic need dry air, potatoes need darkness, and winter squash benefits from warmth. Understanding those differences is essential.
Why Curing Matters
A freshly lifted onion or potato is more vulnerable than it appears.
Its outer skin may still be soft, its neck or stem may contain moisture and small scratches may have been created during harvesting. Placing it immediately into a closed box or sack can trap that moisture and encourage decay.
Correct curing can:
Dry and seal the outer surface
Harden protective skins
Allow minor damage to heal
Reduce moisture around stems and necks
Improve storage life
Reveal crops that are unlikely to store successfully
Curing cannot repair serious cuts, bruising, pest damage or active rot. Damaged crops should be separated and used first.
Choose the Best Crops for Storage
Not every onion, garlic bulb, potato or squash should enter long-term storage.
Select produce that is:
Fully mature
Firm
Free from rot and mould
Undamaged by tools
Free from deep cracks or punctures
Typical of the variety
Set aside anything with soft areas, broken skins, thick wet necks or serious pest damage.
A damaged crop may still be perfectly usable in the kitchen, but placing it among sound produce risks losing more of the harvest.
Harvest in Suitable Weather
Dry weather makes curing easier.
Onions, garlic and potatoes are best lifted when the soil is reasonably dry. Winter squash should be harvested before the first damaging frost and ideally during settled weather.
If persistent rain makes a dry harvest impossible, move the crops promptly to a sheltered, well-ventilated area. Spread them out rather than leaving them piled together.
Do not wash crops intended for curing. Allow attached soil to dry and remove only what comes away easily.
How to Cure Onions
Onions are normally ready to lift when their foliage begins to yellow and fall naturally.
Do not bend healthy leaves deliberately to force the bulbs to mature. While the foliage remains green, it is still helping the plant complete its growth.
Lift the bulbs carefully, loosening the soil first if necessary. Avoid pulling hard on the leaves and do not knock the onions together to remove soil.
Arrange the whole plants in a single layer somewhere dry, sheltered and well ventilated. A greenhouse, shed, covered veranda or airy outbuilding may be suitable, provided it does not become excessively humid or unbearably hot.
The bulbs can also be laid on mesh racks or slatted trays so air can circulate underneath them. If they are placed on a solid surface, turn them occasionally.
Protect curing onions from rain and heavy dew. Strong sunlight can also cause damage during very hot weather, so light shade is useful in hot climates.
How Long Do Onions Need to Cure?
Onions commonly need approximately two to four weeks to cure, although the exact time depends on temperature, humidity, bulb size and air movement.
They are ready for storage when:
The outer skins feel dry and papery
The neck is completely dry
The roots are dry and brittle
No moisture remains around the base
The bulb feels firm
Once cured, trim the roots carefully. Cut the dried foliage above the neck if the onions will be stored loose, or leave it attached if they will be plaited.
Do not cut into the bulb or remove sound protective skins.
Onions with thick or soft necks should be used first rather than placed into long-term storage.
How to Cure Garlic
Garlic should usually be lifted when several lower leaves have turned brown but some of the upper leaves remain green.
Each green leaf contributes a protective wrapper around the bulb. Leaving garlic in the ground until every leaf has died can result in exposed cloves and split bulbs that store poorly.
Loosen the soil and lift each bulb carefully. Do not pull hard on the stem or strike bulbs together.
Keep the complete plant intact during curing. Arrange the plants in a single layer or tie them into small, loose bundles and hang them somewhere dry, shaded and well ventilated.
Avoid making large, tightly packed bundles. The bulbs in the centre may remain damp.
How Long Does Garlic Need to Cure?
Garlic generally requires around three to four weeks, although it may take longer in humid conditions.
It is ready when:
The outer wrappers are dry
The neck and stem are completely dry
The roots feel brittle
The cloves remain firm
There is no dampness or mould around the base
After curing, trim the roots without cutting into the basal plate. The stems can be shortened for loose storage or left in place for plaiting, depending on the variety.
Gently brush away loose, dry soil. Avoid stripping away too many of the protective outer wrappers simply to make the bulbs look cleaner.
How to Cure Potatoes
Potatoes require very different conditions from onions and garlic.
They must be protected from light throughout curing and storage. Light causes greening and an increase in naturally occurring toxins. Green potatoes should not be eaten.
Maincrop potatoes intended for storage are normally left in the ground until their foliage has died back and their skins have begun to set. If blight or severe weather threatens the crop, they may need to be lifted earlier.
Harvest carefully to avoid fork punctures and bruising. Allow surface soil to dry, but do not leave the tubers exposed to sunshine.
Move them promptly into a dark, moderately cool and well-ventilated area. Arrange them in shallow layers or ventilated containers rather than sealing them inside plastic.
How Long Do Potatoes Need to Cure?
Potatoes generally need around one to two weeks for their skins to firm and small surface injuries to heal.
The curing area should be dark, protected from frost and cooler than ordinary indoor living spaces. It should not be as cold as a refrigerator.
After curing, inspect every tuber again. Remove any that are:
Green
Cut or pierced
Soft
Rotten
Badly bruised
Showing signs of disease
Transfer sound potatoes into paper sacks, hessian sacks, slatted boxes or other containers that exclude light while allowing some ventilation.
Do not store them in sealed plastic bags.
How to Cure Winter Squash and Pumpkins
Winter squash and pumpkins need warmth, dryness and good air circulation while curing.
Harvest mature fruit before the first damaging frost. The skin should have developed its final colour and should resist gentle pressure from a fingernail. The stem should be becoming hard and corky.
Cut the stem cleanly, leaving a short section attached. Do not lift or carry squash by the stem. If it breaks away, the exposed area becomes vulnerable to decay.
Wipe away loose, dry soil with a soft cloth. Do not wash squash before curing unless absolutely necessary, because added moisture increases the risk of rotting.
Arrange the fruit in a single layer with space around each one. A warm, dry room, greenhouse or sheltered veranda may be suitable, depending on the local climate.
Protect the fruit from frost, rain and extreme heat. In a greenhouse during a Hungarian summer, temperatures can rise far beyond what is useful, so ventilation and shade may be necessary.
How Long Does Winter Squash Need to Cure?
Most winter squash benefits from approximately one to two weeks in warm, dry conditions.
During this time:
The skin hardens
Small surface scratches may heal
The stem dries
Excess surface moisture disappears
Flavour may continue developing
Turn the fruit carefully if necessary so that the same area is not resting against a hard surface throughout curing.
Some thin-skinned squash varieties do not need prolonged curing and may not store for as long. Storage potential varies considerably between varieties, so use the more perishable fruit first.
Acorn-type squash is often better moved into suitable storage without an extended period of very warm curing.
Know When Curing Has Failed
Check crops frequently throughout the curing period.
Warning signs include:
Soft or sunken areas
Wet patches
Mould
Unpleasant smells
Spreading discolouration
Fluid leaking from the crop
A neck or stem that remains damp
Rapid shrivelling
Remove affected produce immediately and inspect anything it was touching.
Do not attempt to cure a crop indefinitely in the hope that rot will disappear. Curing supports healthy produce; it does not reverse decay.
Move Cured Crops into the Correct Storage Conditions
Once curing is complete, the four crop groups need to be separated.
Onions and Garlic
Store somewhere cool, dry and well ventilated. Mesh bags, open trays, slatted crates or plaits allow air to circulate.
Potatoes
Store somewhere cool, dark and protected from frost. Use containers that exclude light without trapping moisture.
Winter Squash and Pumpkins
Store somewhere dry with good air circulation. They generally prefer slightly warmer conditions than potatoes.
Do not store onions and garlic in the humid conditions preferred by root vegetables. Do not place winter squash in a cold, damp potato store.
Arrange Crops So They Can Be Checked
Avoid creating deep, inaccessible piles.
Store onions, garlic and squash in a single layer where possible. Potatoes can be stored more deeply, but smaller containers make it easier to check them and limit the spread of any decay.
Label each batch with the crop, variety and harvest date. If one variety is known to have a shorter storage life, position it where it will be used first.
Keep containers off damp floors and slightly away from cold external walls where condensation may form.
Inspect Stored Crops Regularly
Curing improves storage life, but it does not make a crop maintenance-free.
Check stored produce every week or two. Remove anything that has begun to soften, sprout, leak or develop mould.
Pay particular attention when the weather changes. An outbuilding that was dry and cool during autumn may become freezing, damp or unexpectedly warm later in the season.
Keeping simple notes in Your Growing Companion can help you compare varieties and storage methods. Over time, it becomes easier to see which onions, potatoes and squash genuinely store well in your conditions.
Give the Harvest Time to Prepare for Storage
Curing is a quiet but important stage between the garden and the store.
Onions and garlic need time to become thoroughly dry. Potatoes need a dark resting period in which their skins can set. Winter squash needs warmth and air circulation to harden its protective surface.
Providing the correct conditions at this stage helps preserve the quality of the crop and protects the work that went into growing it.
Continue Exploring Harvesting & Storage
Return to the main Harvesting & Storage guide for the complete series. The next guide covers freezing, drying and other ways of preserving surplus produce.
