My mom taught me early on that if you want to make a delicious dinner, you'll have to chop onions and garlic. They're staples in most kitchens, and with good reason: They're easy to store, easy to grow and full of amazing flavor. Alliums also have their own unique growing conditions: A long season resulting in fat, heavy-skinned bulbs. If you planted yours in April, they may just be maturing now. Here's how to dig them up and store them without damage.
When to Harvest
Most alliums take their cues from the sun: They mature when the days get long and the soil temperatures are high. You can tell they're ready when the tops start to turn yellow and die. Some people like to bend the tops of onions over to speed this process, but it isn't necessary.
At this point, you want to stop watering. If you live in a dry area, you can leave bulbs in the soil to "cure." In places with regular rain or high humidity, you'll need to get them out of the soil so they can dry.
From the Organic Authority Files
When there are wide temperature fluctuations, your bulbs might flower. This is normal for garlic, but if your onions flower, you need to dig them up and use them right away, or save the seeds for next year.
How to Harvest
The most important thing to remember when digging up your bulbs is not to damage their protective outer layers. If you do, it leaves them exposed to disease and dryness. I like to use a cultivator fork to tear up the soil around the bulb, then pull it out by hand. Wet the soil first if it's hard or rocky, and take the time to pull your bulbs gently without damaging them.
Before you store bulbs, they need to cure (dry out) in a dark, dry place. As I mentioned, desert gardeners can let them cure in the ground. Otherwise, lay them out on newspapers in the garage or basement for two weeks, until the necks turn brown.
When your bulbs are completely dry, cut off the onion necks to about an inch long. You can do the same with garlic, or braid the stems for a more traditional garlic "wreath." Sort out the biggest garlic heads, and save them to plant in the fall. Everything else can be stored in a cool, dry place (35 to 45 degrees is ideal) for up to several months. Avoid keeping bulbs in the sun, as they'll age much faster that way.
Enjoy... and don't skip the mouthwash!