Curing
After drying the onions in the open for a day or so, it’s time to bring them under cover for a second, longer drying or “curing” process.
Some people cut the tops off the onions before curing, but that’s not strictly necessary. However, if you do trim the top leaves, don’t cut them any closer than one inch from the bulb. Otherwise the neck won’t dry out, and the onion could rot in storage.
To cure the onions, spread them out in any warm, airy place out of the sun, such as on a porch. Turn the bulbs a couple of times to promote even drying.
If you need to cure onions without overhead protection, do not use heavy coverings like canvas or plastic since they trap moisture the onions will never get really dry. Instead, use a sheet to keep the onions out of direct sunlight and rain showers. The sheet and the onions will dry out rapidly together after a shower.
You don’t want any wet spots on the onions when you put them in storage, so cure (dry) them really well. This can take two to three weeks depending on the amount of humidity or moisture in the air. After curing them, place onions spread out in a cool, dry area with plenty of air movement.
Curing Basics
Here are the basics of curing:
- Sun dry for just a short time.
- Cure just the onions you’ll store; separate the soft, young and thick-necked bulbs and use them first.
- Cure thoroughly in a warm, well-ventilated area away from direct sun.
- Don’t crowd onions during curing; give them room to breathe.
- Onions are ready to store when the skins rattle and the roots are dry and wiry.
Article by National Gardening Association Editors.