White onions are the mild-mannered member of the onion family, and that mildness is exactly why people grow them. Their flesh is crisp, juicy and sweet with very little bite, which makes them the onion of choice for fresh salsas, salads, pickling and any dish where you want onion flavour without onion heat. What they are not is a long-storage onion: white onions have thin skins and high moisture, so they are grown to be eaten fresh, and harvesting them at the right moment and handling them gently is what keeps them firm and sweet instead of soft and spoiled.
White onions take 90–120 days to mature, according to the Garden Grove crop data. They are a hardy vegetable in the Amaryllidaceae family with moderate water needs, so they tolerate cool weather and grow through a long season. Like all bulb onions, they tell you they are ready through their tops — and the tops of a white onion are easy to read. For the full growing picture, see our growing guide for white onions, and use the Harvest Date Calculator to work out your lifting window from your sowing date.
White onions at a glance
| Growing factor | What white onions need |
|---|---|
| Days to maturity | 90–120 |
| Category | vegetable |
| Family | Amaryllidaceae |
| Cold tolerance | hardy |
| Water needs | moderate |
Signs a white onion is ready to pick
The tops are the first and most reliable sign. When white onions are ready, the green tops yellow, soften and fall over — most of the tops in a row will flop within a few days of each other. This is the plant finishing its work: the bulb has stopped growing and the neck is starting to seal itself. When roughly half to most of the tops have fallen, the crop is ready to lift. Do not wait for every top to be brown and dry.
The bulb is the second sign. Brush the soil away from the top of a bulb and look: a ready white onion is well rounded and firm, with clean white papery skins that feel dry and rustle when touched. The neck — where the leaves meet the bulb — should feel soft and papery rather than thick and green. A thick, green neck means the bulb is still growing and will not store at all, because moisture enters through the neck.
Size is the third check, and white onions are often a little smaller than yellow storage types — that is normal, not a failure. Compare bulbs in your own row, and pull one as a test: it should be firm all over, with tight, dry outer skins and no soft spots or green colouring at the neck. White skins show bruising and dirt more than coloured skins do, so handle the test bulb gently. For the long-storage onion, see our guide to when to harvest yellow onions, and for the fresh-eating coloured onion, see when to harvest red onions.
How to lift white onions without damaging them
Lift onions, do not pull them. Loosen the soil around each bulb with a fork first, working a little way out from the bulb so you do not spear it, then lift the bulb gently by its base. Pulling an onion out of firm soil tears the roots and bruises the bulb, and a bruised white onion — with its thin skins — rots faster than any other type.
Handle the bulbs as gently as you can throughout the harvest. Do not throw them into a bucket, do not knock them together, and do not cut the tops off immediately — the tops are part of the curing process. Lay the lifted bulbs in a single layer on the soil or on a rack, tops and all, and let them dry in the sun for a day or two if the weather is dry. If rain is forecast, move them under cover straight away, because wet white onions are the hardest of all to cure.
The best time of day to harvest
Lift onions on a dry, sunny morning, after the dew has dried. Dry bulbs cure far better than wet ones, and a sunny day gives the curing process a good start. The soil should be dry enough to crumble away from the bulbs rather than sticking to them in wet clods.
Avoid lifting white onions in wet weather or from sodden soil if you possibly can. Wet bulbs take much longer to cure, and moisture trapped in the neck is the main cause of rot in storage — and white onions, with their thin skins, are the least forgiving of damp. If the tops have fallen during a wet spell, lift them anyway, because leaving them in wet soil is worse, and get them under cover to dry as quickly as possible.
How often to pick
Onions are a single-harvest crop: the whole row comes ready at roughly the same time, and you lift it in one or two passes. Once the tops have fallen, do not leave the bulbs in the ground for more than a few days — they can start to regrow in wet weather, and the thin skins can split. Lift the row, cure the crop, and the harvest is done.
You can also pick white onions earlier for a different use. Young white onions pulled while the tops are still green make superb spring onions — mild, crisp and sweet, and one of the best uses of a thick sowing. Thin the row by pulling the smallest plants as spring onions, and leave the rest to bulb up. Because white onions are hardy, the season is long and forgiving, but the final lift should happen before prolonged wet autumn weather sets in. See Zone 6 white onions for an example of seasonal timing, and check your local extension service for lifting dates in your area.
What happens if white onions are left too long
A white onion left in the ground after its tops have fallen will not get bigger — it will get worse. In wet weather the bulb can start to regrow, sending out new green shoots, and the thin skins can split and let in rot. In dry weather the bulb dries out and loses weight and flavour.
A bulb left too long is also more likely to be damaged by onion fly and other pests, and to rot from the base. If you find a bulb has started to regrow or has gone soft, use it straight away rather than trying to store it — it will not keep. White onions give you less margin for error than any other onion, so when the tops fall, lift promptly.
How to store white onions
Short term, white onions are best eaten fresh, and that is the honest truth about them. After a short cure, store them in a cool, dry, well-ventilated place — a mesh bag, a basket or a crate, in a single layer if you can, somewhere cool and dark with good airflow. They keep for a few weeks this way, and they are at their best in that window.
Curing still matters, even for a short-storage onion. Spread the lifted bulbs in a single layer in a warm, dry, airy place for a couple of weeks, until the outer skins are papery and the neck is completely dry and tight. Turn the bulbs occasionally so they dry evenly. Only store bulbs that are firm and sound; any soft or damaged bulb should be used first, and white onions are wonderful pickled — pickling is the best long-term use for a white onion glut, because their mild flesh takes up vinegar beautifully.
Do not store white onions in the fridge or in a sealed plastic bag, where damp and cold encourage rot and sprouting, and keep them away from potatoes, which release moisture and gases that make onions sprout. Use white onions first, before your yellow storage onions — that is the right order for the pantry.
If you grow a lot of onions and want to plan quantities, the Vegetable Yield Estimator can help you work out how many to plant next season.
Succession and continuous harvest tips
Onions are not succession-sown for bulb harvest — one sowing gives one crop. The way to get a longer supply is to grow different types side by side: white onions for fresh eating and pickling, yellow onions for long storage, and red onions for salads. You can also sow a second, later batch of white onions for young salad onions if your season is long enough.
Keep the bed weed-free while the bulbs are swelling, because onions compete badly with weeds, and water steadily until the tops start to fall — then stop watering entirely, because dry soil helps the bulbs cure in the ground. Do not feed onions late in the season, or the tops will stay green and the bulbs will not ripen. Browse the full guides hub for more harvest timing advice, and check your local extension service for varieties that perform well in your climate.
Frequently asked questions
When are white onions ready to harvest?
When the tops yellow and fall over, the bulb is well rounded with clean white papery skins, and the neck feels soft and papery. Maturity is typically 90–120 days.
How long do white onions last in storage?
White onions are a short-storage onion: a few weeks in a cool, dry, ventilated place after curing. They are best eaten fresh or pickled — for long storage, grow yellow onions.
How do I cure white onions?
Spread the lifted bulbs in a single layer in a warm, dry, airy place for a couple of weeks, until the skins are papery and the neck is completely dry. Turn them occasionally and only store firm, sound bulbs.
Can I eat white onions straight after lifting?
Yes, but they taste better after a short cure, which dries the skins and concentrates the flavour. Young onions pulled early are excellent as spring onions.
Why did my white onions go soft in storage?
They were probably stored before curing fully, stored damp, or bruised at lifting. White onions have the thinnest skins of all, so cure them thoroughly, handle them gently, and check your local extension service for storage advice suited to your area.