Garden · Harvest & storage
Onion & garlic curing time calculator
Fresh-harvested garlic, onions, and shallots all need to cure before storage, drying down the outer skins and sealing the neck so the bulb doesn't rot in the pantry. Cure them too briefly and they spoil early. There's no need to over-cure, but rushing it is the more common mistake. How long that actually takes depends on the species and, just as much, on how humid your curing space is.
Estimated curing time
12–24 days
Curing is done when the outer skin is dry and papery and the neck (or stem) is tight and hard, not just when the calendar says so. Cure in a single layer or loosely hung bundles with good airflow, out of direct sun.
What to actually buy
Small Digital Hygrometer
Curing speed depends directly on the humidity input above, and most garages, sheds, and pantries run more humid than people assume, especially in late summer. A small hygrometer left in the curing space tells you which end of the estimated range to expect instead of guessing.
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How this is calculated
UMass Amherst's garlic harvest, curing, and storage fact sheet puts garlic curing at roughly 2 to 4 weeks in a dry, well-ventilated space. This calculator applies a similar baseline to storage onions, which cure by the same neck-and-skin-drying process, a shorter window to sweet or short-storage onions (which are grown for eating soon rather than long storage and don't need as long a cure), and a window in between for shallots.
Humidity is a real driver of drying speed, not just a minor factor, since curing is fundamentally a moisture-loss process. This calculator applies its own reasonable adjustment for curing space humidity: faster in a dry space, slower in a humid one, since that specific adjustment isn't a separately published figure, it's applied to the baseline ranges above rather than treated as a precise multiplier.
The date range is a planning estimate. The real signal that curing is done is physical: the outer skins are dry and papery, not soft or green, and the neck or stem has tightened down hard rather than staying thick and moist. Check bulbs directly before storing rather than going by the calendar alone.
Frequently asked questions
Can I cure onions and garlic in direct sun to speed things up?
No, direct sun can scald the outer layers and actually damage the bulb rather than speed up curing safely. Cure in a shaded, well-ventilated spot, a garage, covered porch, or shed with airflow works better than a sunny spot.
What if my curing space doesn't fall clearly into "dry" or "humid"?
Pick whichever is closer, or use the dry-space estimate as your earliest check point and the humid-space estimate as your latest, then judge by the bulb's actual appearance in between. A basic hygrometer in your curing space removes the guesswork if you cure regularly.
Should I trim roots and tops before or after curing?
After. Leave roots and tops attached during curing, since they help draw remaining moisture out of the neck as the bulb dries. Trim down to about an inch of neck and remove the roots once curing is finished and you're ready to store or braid.
Can I wash the bulbs before curing to remove field dirt?
Better to brush off loose dirt dry and skip washing before curing. Added moisture from washing works against the whole point of curing and can encourage rot before the bulb has a chance to dry down properly.