Harvesting Onion Plants
Harvesting onions is quite different than plucking an ear of corn off the stalk, or snipping off a bell pepper. The way you harvest your onions will have a direct effect on the amount of time they will last in storage.
All onions (long-day and short-day) are cured and stored in the same way, which keeps things simple. Learn about the best techniques to keep your onions for the longest time possible.
NOTE: This is part 9 in a series of 9 articles. For a complete background on how to grow onion plants, we recommend starting from the beginning.
Harvesting
Your onion bulbs will start moving into the end of their growing phase in summer, depending upon the weather, the varieties you chose and when you planted them. It normally takes about two to four months for onion bulbs to mature from the time they are planted. You’ll know when it’s time to harvest because the tops of the onions will turn brown and fall over. The plant will have about 13 leaves at harvest time.
If possible, pick a sunny day to harvest your onions when you can work early in the morning and the soil is not wet. When the day arrives, use a garden fork to very gently loosen the soil around the bulb, taking care not to damage it—doing so can dramatically affect storage quality. Pull up the onion by grasping the top of the bulb at the base of the leaves (rather than tugging on the leaves themselves) and carefully work the bulb out of the soil.
Some important things to remember about harvesting onions:
- Do not remove the leaves yet.
- Dry the onions in the sun for two to three days, in a breezy spot if possible.
- Shake the bulb or gently brush it off to dislodge any loose soil—do not wash it!
Curing Onions
Properly curing your onion bulbs is a critical step in avoiding decay. The drying process dehydrates the papery sheaths. seals off the neck and protects the bulbs against deterioration.
Wait for a dry weather forecast, lift your bulbs and dry them in a sunny, breezy spot for two to three days, as described above. Once the necks are completely dry and the stems are no longer green, you can trim the leaves back to within 1" of the bulb, and trim off the unsightly roots off the bottom. If any onions still have green necks, use them immediately because they will not keep. You will know the onions are cured when the skins take on a uniform color and the necks don’t “slip” when you pinch them.
Once the onions are fully dry, shake off any loose soil (or use a soft brush) - do not rinse!
It’s not mandatory to cure your onions—that’s only necessary if you plan to store them for any length of time. Uncured bulbs will last about 3 weeks.
Storing Onions
Bring your cured onions indoors and keep them in mesh bags, a wire basket or corrugated cardboard box with holes punched out around the sides. The only real storage rule is that the “container” needs to allow plenty of air circulation so the onions remain dry, and that your storage space is cool (45º-55º is ideal). As a rule, use your sweeter (short-day) onions first, as the more pungent varieties store longer.
Check occasionally for any signs of rot and remove that bulb to avoid contamination of the others.
