Here’s how to harvest onions and cure them for long storage.
Actually, you can harvest onions throughout the entire growing season. In early summer, you can harvest 1/3 of the tops of each plant as green onions. Later, as the bulbs form, you can use immature bulbs as you need them. Finally, there comes the time when the entire crop is ready to be pulled. This big harvest usually occurs late August to early September in Zone 2-3.
When to Harvest Onions
Here are the signs that your onions are ready to harvest.
- tops have turned yellow
- tops have flopped over and are lying on the ground
- onions have bolted, ie. they’re sending up flower stalks
- snow is covering your onions!
If most, but not all of the onion tops have fallen over, manually bend over the remaining tops to force the onion to focus its energy on the bulb. After another 5 days of being flopped over, it’s time to harvest and cure your onions.
When the onions are ready, you really should harvest them. While onions are tolerant of frost and may look like they’re doing just fine in the soil, leaving them in the ground puts them at risk of being infected by various organisms (bacteria, fungus, onion fly maggots, thrips, etc) that impact the usability or storeability of your onions. It really is best to get your onions out of the ground and properly cured (dried).
Harvest on a nice sunny day when your onions are dry, ie. – if it rained the night before or there is heavy dew wait until they get a chance to dry before picking. Moisture is not good if you want to store your onions for an extended period.
To harvest, simply pull up on the neck of the onion. The occasional stubborn onion may need a small trowel to help loosen the soil around it.
When pulling the onions look them over carefully. Sort out any onions that are soft, split or have any other signs that they should either be used right away or be tossed in the garbage. (Avoid leaving onions with rot in the garden or in the compost to help prevent the spread of disease.)
Believe it or not, onions are pretty sensitive to bruising, so be gentle. Lightly brush off any dirt and grimy layers of onion paper.
Ideally, leave the onions lying on top of the soil for two to three days to begin the drying process. Since our garden plot sometimes gets unwanted visitors helping themselves to produce, I bring my onions home with me and lay them outside in my backyard for a few days.
After the initial drying, I place them in a single layer on a piece of cardboard in a dry, dark place (my garage) where they can cure – for another 4 weeks.
Curing the onions sufficiently will allow the skins to turn into brown papery wrappers and the necks to close up and keep out unwanted moisture. Any dampness will lead to rot and even just one rotten onion can end up spoiling a whole batch.
Finally, after all that drying, they’re ready to put in mesh bags and be stored for several months.
Getty Stewart is an engaging speaker and writer providing tasty recipes, time-saving tips, and helpful kitchen ideas to make home cooking easy and enjoyable. She is a Professional Home Economist, author of Manitoba’s best-selling Prairie Fruit Cookbook, Founder of Fruit Share, mom and veggie gardener.