Onions are great crops to grow because you can harvest them whenever you want—thin the seedlings and use them like scallions or wait until the plants stop growing for mature onions. But how do you know when an onion plant stops growing? That’s a good question; just read on for the answer.
When onions are finished growing the leaves turn yellow, starting with the lower leaves. Then the stalks start falling over, putting a final end to the growth. If you want to use onions right away, go ahead and pick some. But if you plan to store them to use later, you better leave the plants in the ground for 10-14 days to cure.
The next step is to pull the onions up (preferably on a sunny day) and let them rest on top of the soil for a day or two until the roots dry up. Cutting off the leaves is optional, but if you do, leave an inch of stem above the bulb to prevent rot.
Now your onions are ready for the second round of curing. Spread them out in a warm, well-ventilated place out of the sun—a porch is great—for a couple of weeks. The dryer the air the shorter the time needed for curing. When the onions look like the ones you get in the market, with dry paper-thin skins, put them in mesh bags and dry them some more.
The dryer they are the better they’ll get through the winter in a cool, moderately dry, airy space like a root cellar.
Of course, not all onions are grown for their bulbs. The roots and leaves of bunching onions can be harvested at any time during the growing cycle—the earlier the harvest the milder the taste. Scallions are perfect when they are six inches high.
Want more information on harvesting onions?
Find more tips from the experts at these websites:
Home Gardening: Growing Onions. PDF from Alabama Cooperative Extension System
Lynne Lamstein gardens in Maine and Florida and is currently working on a sustainable landscape. She has a degree in ornamental horticulture from Temple University.