How to Harvest, Cure, and Store Onions for Long-Lasting Flavor
Few moments in the garden are as satisfying as pulling up plump onions after months of careful tending. If you’ve grown onions before, you know that harvesting them at the right time and curing them properly is the secret to enjoying your crop for months to come. Over the years, I’ve grown Walla Walla sweets, a Northwest favorite, and I’ve picked up some reliable tricks for drying and storing them.
When to Harvest Onions
The best signal that onions are ready to harvest is in their tops. As onions reach maturity, the green stalks naturally flop over and begin to yellow. When about half to three-quarters of the tops have fallen, it’s time to stop watering and let the bulbs finish curing in the ground for about 7–10 days. This pause toughens the outer skins and prepares them for long-term storage.
For sweeter onions like Walla Wallas, keep in mind that they don’t store quite as long as pungent varieties. Plan to use them within a couple of months, or preserve them by freezing, pickling, or dehydrating.
How to Cure Onions
Curing is essential for extending the shelf life of your onions. It allows the outer layers to dry into a papery skin that protects the bulb. Here’s the process I use:
Lift Carefully – Use a garden fork to loosen the soil and gently pull onions by their tops. Avoid bruising, as damage shortens storage life.
Air Dry in Layers – I use a simple setup that’s worked for years: a cheap greenhouse frame I bought on Amazon (without the plastic cover). I stack several layers of onions across it in my garden shed. The open design lets air circulate around the bulbs so they dry evenly.
You can find a similar affordable greenhouse frame here on Amazon.
Provide Good Ventilation – Keep onions in a dry, shaded, well-ventilated spot for two to three weeks. During this time, their outer skins will tighten and the necks will dry down completely.
Trim and Store – Once cured, cut tops back to 1–2 inches and snip roots. Store in mesh bags, crates, or baskets in a cool, dark location.
Onions drying on the racks in my shed.
Storage Tips
Temperature & Humidity – Ideal storage conditions are 32–40°F with 65–70% humidity. A basement, garage, or shed can work well if it stays cool and dry.
Check Regularly – Even well-cured onions can occasionally sprout or rot. Check your stash every few weeks and remove any soft bulbs.
Use by Variety – Eat sweet onions like Walla Wallas first, and save pungent storage varieties (like Copra or Yellow Globe) for later.
Final Thoughts
Harvesting onions is only the first step—curing and storing them properly makes all the difference. With a little patience and the right setup, you can enjoy garden-fresh onions deep into the winter. My greenhouse frame drying rack has been one of the simplest, most effective tools for this process, and I can’t recommend it enough for backyard growers.