Harvesting onions at the right moment is the difference between a crop that tastes superb and one that is tough, bitter or bland. Pick too early and you lose flavour; pick too late and you lose texture, and the plant slows down. This guide covers when to harvest onions — the signs that tell you when one is ready, how to pick it without damaging the plant, the best time of day to harvest, how often to check, what happens if fruit is left too long, and how to store the harvest, both for a few days and for months. The timing below uses the published range for this crop, 90–120 days to maturity, which varies by variety, climate and soil, so treat it as a guide and judge each plant by what you can see and feel.
Onions are a vegetable in the Amaryllidaceae family, with hardy cold tolerance and moderate water needs. They need full sun and are usually both. Knowing those basics helps you judge harvest time, because a plant that has been watered evenly and grown in the right conditions ripens evenly, while a stressed plant ripens unevenly and often disappoints. Keep a simple note of when you sowed and when you first picked — after one season you will have a record far more useful than any general guide. As with all the timings in this guide, these are broad published ranges, not exact dates for your garden, so check your local extension service for your area.
Onions at a glance
| Detail | Guidance |
|---|---|
| Days to maturity | 90–120 days |
| Family | Amaryllidaceae |
| Category | vegetable |
| Cold tolerance | hardy |
| Water needs | moderate |
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Spacing | 4–6 inches |
| Sowing | both |
If you are still growing this crop, the growing guide for onions covers soil, spacing, water and care in full, and the Zone 13 page for onions covers timing in a frost-free climate. The harvest date calculator can help you work out roughly when a sowing should be ready, and the vegetable yield estimator helps you plan how much to grow.
Signs that onions are ready to pick
The best harvest decisions are made with your eyes and hands, not with the calendar. Days to maturity is a useful starting point, but weather, variety and watering all shift it, so learn the signs for this crop and check plants regularly once the harvest window opens. For onions, the signs are:
- Tops fall over: The clearest sign: the green tops yellow, soften and fall over. When about half the tops have fallen, the bulbs are ready to lift.
- Bulbs feel firm: A ready bulb feels firm and heavy, with a dry, papery outer skin. Soft or wet necks mean the bulb is not ready — or it has started to rot.
- Neck dries: The neck, where the leaves meet the bulb, should be thin and dry. A thick, green neck means the bulb will not store well.
- Size for the variety: Bulbs should be a good size for the variety you planted — check your seed packet or plant tag. Small bulbs are still usable, just less impressive.
The single most useful habit is to check plants every day or two once the first fruit starts to ripen, and to pick a test fruit if you are unsure. One test tells you more than a week of guessing. Taste it, look at it, feel it — and then pick the rest of the row at the same stage. If the test fruit is not ready, leave the row alone for a few days and test again. Over a season you will learn to read this crop at a glance, and harvesting will become quick and confident.
How to pick onions without damaging the plant
Lift onions with a fork on a dry day, loosening the soil underneath and lifting the bulbs gently by hand. Do not pull them by the tops, which can tear the neck and let rot in. Leave them on the soil surface or on a rack in the sun for a day or two to dry, turning them once, then move them to a dry, airy place to cure.
Whatever the crop, the rules are the same: use clean, sharp tools, support the plant while you pick, pick in the cool of the morning when the produce is crisp, and never yank or tear. A clean cut heals fast; a tear leaves an open wound that disease can enter, and a damaged plant produces less for the rest of the season. Keep your tools clean between plants, wash your hands before handling food, and put harvested produce in a clean basket or trug rather than on the soil, where it picks up dirt and pests.
Best time of day and how often to pick
Pick in the morning, after the dew has dried but before the heat of the day, when the produce is cool, crisp and full of water. Produce picked in the heat of the day wilts fast and does not keep as well. Onions take 90–120 days to maturity and are usually harvested in one go, when the tops fall. Lift them all within a few days of each other, and cure them properly — curing is what makes them store.
Regular picking is not just about getting the best flavour — it is also how you keep the plant producing. Most fruiting vegetables slow down or stop setting new fruit when mature fruit is left hanging, because the plant has done its job. Picking regularly tells the plant to keep flowering, and in a frost-free climate that can mean months of extra harvests from the same plants.
What happens if onions are left too long
Left too long in wet soil, bulbs can rot or sprout again, and the necks stay thick and wet, which spoils storage. Lift promptly once the tops have fallen, and cure them in a dry place rather than leaving them in damp ground.
The cost of leaving produce too long is not just one spoiled fruit. An over-mature fruit left on the plant can slow the whole plant down, attract pests that then move on to healthy fruit, and spread disease from rotting tissue. A daily or every-other-day check is the cheapest insurance in the garden: it takes a few minutes, and it catches problems while they are still small. If you do find over-mature fruit, remove it promptly — compost it if it is diseased, and use it in cooking if it is simply past its best.
How to store onions
Fresh, uncured onions keep for a week or two in a cool place. Use any with thick necks or damage first — they will not store.
Cure onions for two to three weeks in a dry, airy, shaded place until the necks are completely dry and the skins are papery, then store them in a cool, dark, ventilated place in a mesh bag or braided by their tops. Properly cured onions keep for months. Check them regularly and use any that soften first.
A good rule for storage is to sort the harvest as you pick it: the best produce keeps longest, so store the firm, unblemished fruit and eat the damaged or softest pieces first. Check stored produce regularly and remove anything that softens or spoils, because one bad piece can spoil the rest. Label anything you freeze or dry with the crop and the date, so you know what you have and when to use it.
Succession sowing and continuous harvest
Onions are a long-season crop at 90–120 days to maturity, so succession sowing is less useful than staggering varieties — grow an early variety and a storing variety together, and sow a second batch a few weeks after the first for a spread of harvests.
Succession sowing is the answer to the two most common harvest problems: a glut followed by nothing, and a crop that finishes all at once. Sow or plant a little, often, rather than a lot at once, and you will have a steady supply instead of a feast and a famine. Keep notes on what you sowed and when, so you can repeat the timing that worked and adjust the timing that did not.
Common harvesting mistakes
- Pulling onions by the tops, which tears the neck and lets rot in.
- Skipping the curing stage and storing damp onions, which rot fast.
- Leaving bulbs in wet soil after the tops have fallen.
- Storing onions in the fridge or in a sealed bag, where they go soft.
Most harvesting mistakes come from the same place: guessing instead of looking, and leaving the garden alone for a week at the critical moment. A short daily check, a test fruit when you are unsure, and picking little and often will avoid nearly all of them.
Frequently asked questions
When are onions ready to harvest?
When the tops yellow and fall over — about half the tops down is the usual moment. They take 90–120 days to maturity, and the bulbs should feel firm with a dry neck.
Do I need to cure onions?
Yes, if you want them to store. Cure them for two to three weeks in a dry, airy, shaded place until the necks are dry and the skins are papery.
Why did my onions rot in storage?
Usually because they were stored damp, with thick green necks, or in a sealed container. Cure them fully, store them in a ventilated place, and use any soft ones first.
Can I eat onions with thick necks?
Yes — use them fresh within a week or two. Thick-necked bulbs do not store well, so eat them first rather than storing them.
How long do cured onions keep?
Properly cured and stored in a cool, dark, ventilated place, onions keep for months. Check them regularly and remove any that soften.
Related guides
For more harvesting help, browse the guides hub, plan your next sowing with the planting calendar, and try the harvest date calculator and the vegetable yield estimator. If you are growing in a frost-free climate, the Zone 13 page for onions and the growing guide for onions are the best next reads. And as always, check your local extension service — local advice beats any general guide for your soil, your weather and your varieties.