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Harvest, Storage & Post-Harvest TimingOnion Harvest and Curing Calendar
Onions signal readiness through their tops. A good cure after lifting is what decides how long they keep.
Key points
- Harvest when the tops have fallen, not by a set date.
- Cure in a warm, dry, shaded, airy place until necks are tight.
- Handle gently and store cool and dry with airflow.
- Use sweet types and thick-necked bulbs first.
- Match day-length type to your latitude before you plant.
How do you know when onions are ready?
Onions are ready when the tops fall over and begin to yellow and dry. Many growers wait until most of the tops have fallen. If you pull them too soon, the necks stay thick and the onions rot in storage.
Onion bulbing depends on day length and variety, so timing differs among types. Check your state extension for the types that suit your area.
Short-day, intermediate-day and long-day onions respond to day length differently, and a type grown in the wrong region may not bulb well at all. Your extension office can tell you which group suits your latitude. A late cool spell can delay the finish, and a hot one can speed it, so keep checking every few days as the tops begin to go.
How does weather affect the calendar?
Cool, wet weather slows the finish, and hot, dry weather speeds it up. Stop irrigating as the tops begin to fall, as extension guidance advises, so bulbs dry down. Choose a dry spell for lifting if you can.
For example, if rain is forecast just as your tops fall, lift on the last dry day and cure under cover rather than leaving them in wet soil.
Plan to have a covered space ready before the harvest, since the curing area needs to be cleared and set up when the tops fall. A porch, a shed or a barn aisle with fans often works.
- Watch the tops, not the date
- Stop watering as tops fall
- Lift on a dry day
- Move to a covered curing spot
How do you lift onions?
Loosen the soil with a fork and lift gently. Leave the tops on and shake off loose dirt. Avoid bruising and cutting, since damaged onions rot first.
Leave onions in the field briefly to dry, then move them to the curing area before they can scald in strong sun or get wet again.
Handle onions as you would eggs: set them down, do not toss them, and do not stack crates so high that the bottom layer is crushed. Mark damaged onions for early use.
How do you cure onions?
Spread onions in a single layer or hang them in a warm, dry, shaded and airy place. Good airflow is more important than heat. Fans can help in humid weather.
Curing is done when the necks are tight and dry and the outer skins are papery and rustle. Extension guides describe the signs and the time it usually takes.
In humid years, extra airflow and thin layers help. If the weather stays wet for a long period, ask your extension office for ways to finish curing indoors. If you have only a small crop, a screen set across two sawhorses in a shaded breezeway does the job.
How do you trim and store onions?
After curing, trim roots and cut tops to the length you want, or braid if the tops are still strong. Remove loose skins and sort out any onions with thick, wet necks or soft spots. Use those first.
Store in a cool, dry place with airflow, such as mesh bags, crates or hanging braids. Keep them away from potatoes, since moisture and gases can affect both.
Moisture is the enemy of stored onions, so keep the storage area dry. Mesh or slatted containers let air move around each bulb.
What mistakes cause onions to rot?
The common ones are harvesting before the necks have closed, curing in damp conditions, piling onions deep, and bruising. Sweet onion types tend to keep for a shorter time than pungent storage types, so use them first.
Check stored onions every few weeks and remove any that are soft or sprouting.
Worked example: if your onions are stored in crates and you notice a soft onion on top, check the ones touching it. Rot spreads quickly, and a weekly check saves the rest.
What do you record?
Note when the tops fell, when you lifted, how long curing took and how the crop held. These notes tell you what to adjust the next year.
Your county extension office can help you match varieties to your day length and storage plans. Keep notes on variety names so you can repeat the ones that kept best.
Sources and further reading
Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.