Harvesting Onions: GardenZeus Tips

Your onions have been growing slowly but surely.  But how do you know when they are really ready for harvest?

Leaves and roots of bulb onions can be harvested at any time after they reach a desired or reasonable size for eating, from baby scallions to mature bulbs. If harvesting before maturity, you may need to brush soil away from around onion roots or probe gently with your fingers to determine root size before harvesting.

If you wish to harvest individual onion leaves throughout the growing season and still have bulbs at maturity, harvest only a small portion of leaves, no more than 15% to 20% of the plant’s total leaf surface, at one time.

Because they tend to have shallow roots, onions can often be pulled directly from the ground by grasping at the base of the leaves and pulling firmly. It may be necessary to push a spading fork, trowel, or shovel into soil about 2 to 6 inches inches from the onion root(s) and gently loosen the soil before harvesting.

Traditionally, mature bulb-onion crops are often harvested in their entirety about 7 to 14 days after the tops begin falling, or after about half to 2/3 of the tops are down.

While most short-day onions do not store well, the occasional pungent variety, such as Red Creole, will store for several weeks to several months. To harvest bulb onions for storage, allow them to grow to full maturity. When half to 2/3 of onion tops have yellowed and fallen, harvest the entire crop with tops still attached. Rinse and clean the bulbs with plain water to remove soil and allow them to dry outdoors for 2 to 3 weeks, arranged with space between bulbs for air circulation. The first few days of drying are best in sunlight during cool weather, or in shade during warm-to-hot weather, and thereafter bulbs should be dried in natural light with shade, and out of the rain.

It’s best to stop watering bulb onions when 10-25% of the tops have fallen. If you discontinue watering too early, you may decrease your yield slightly, but continuing to water bulb onions as they go dormant can result in disease, split roots, and other problems.

Onions that are harvested when immature generally do not store well and are best for fresh eating.

Onions that begin to bolt at any time during the growing season should be harvested and eaten immediately. They will become bitter or unpalatable as the plant goes to seed, and will not store well.

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Other articles of interest regarding harvesting vegetables include:

Potatoes: Harvesting, Storing and Curing

Harvesting and Curing Varieties of Winter Squash