Harvesting Onions Tips

You can always tell when onions have stopped growing. The leaves will lose their color, weaken at the top of the bulb and flop over. Each year a few new gardeners watch the leaves die and wonder, “What’s wrong?” There’s nothing wrong; it’s nature’s plan. The leaves’ job is done – they’ve put the last of their energy into the bulbs.

Let most of your onion tops fall over by themselves – maybe 80% or 90% of them – then bend over the rest of the tops. Once they’re down, leave the bulbs in the ground for another 10 days to two weeks to mature fully. It’s not good to leave the onions in the ground for longer than two weeks after the tops die because they become open to organisms that can cause rot in storage, or they might even start growing again.

Pull your onions up on a sunny day if you can, then let them sit in the sun for another day or so to dry (in hot climates this usually takes just a few hours). This drying kills the root system at the bottom of each bulb. The roots will be like little brittle wires when they’re dry.

Picking the right day to pull the onions can determine how well the onions will keep. If you harvest them after some rainy weather they’ll have a lot more moisture in them and won’t dry out as well.

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.

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.