When to Harvest Onions

Onions are remarkably easy-to-grow, but it is vital to understand how to properly harvest onions as well as how to store them so that you can get the most of this cooking staple. Recognizing when to harvest onions will yield the best flavor and quality of your allium varieties.

Follow our tips and tricks as we guide you on how and when to harvest your onions to bring these precious gems from farm to table. We’ve even included some of our favorite show-stopping varieties to suit all of your cooking needs.

How to Harvest Onions?

Bridget Ayers, a gardener in zone 10b, shows us her favorite methods for harvesting flavorful onions. Follow Bridget’s tips and tricks on how to harvest, cure, and store onions to bring these precious gems from garden to table.

Whether your garden is big or small, make the most of your space with these tips and watch the full How to Harvest, Cure, & Store Onions video on the Kellogg Garden Youtube Channel.

When to Pick Onions?

By midsummer, when the bulbs start to fatten up, you can begin harvesting individual onions as needed.

How to Know When Onions Are Ready to Harvest?

When the area right above the neck (the place where the leaves meet the bulb) starts feeling soft, the transfer of carbohydrates from the leaves to the rings has finished meaning the final cell division within the rings has occurred. At this stage, you should water less frequently to prevent sour skin and black mold occurring in wet soils.

When some of the tops fall over, this reflects 100% soft neck, even though not all the tops are down. If you are planning to consume the onions right away, you can pull and enjoy them. There is good skin development at this stage and adequate green tops to prevent sunscald during drying.

Examine all the leaves, particularly the most recent one to appear (last leaf). The leaf sheaths mature and dry from the oldest to the youngest leaf. If you pull the onions from the soil before the last leaf is dry, rot could occur during storage. The neck cavity or top of the onion should not be sunken or soft before lifting the onions out of the soil.

How to Harvest Green Onions?

Green onions fall into a category of bunching onions and can be used in the kitchen in a variety of ways and they lack the large bulbous quality of traditional onions. They are harvested young and have a much milder flavor than its storage onion cousins.

Harvest green shoots when they are approximately 6-7 inches tall. The plant will become more robust and tougher to pull if you wait much longer than that. If you have missed the ideal timeframe for harvesting your green onions and they have bolted and gone to seed with the formation of flower stalks, all hope is not lost for your crop.

Pull up the onion bulbs immediately and use the onions soon after harvest. These onions will not store well, but they can still be utilized right away.

Recommended Varieties

‘Evergreen’ is a bunching green onion variety that produces long, slender stalks with tiny white root bulbs.

‘Tokyo Long White’ are heat and cold resistant variety of green bunching onions that produce robust greenish-blue tops with slender white bulbs.

Harvesting Traditional Storage Onions

Traditional storage onions can be harvested at any time for fresh consumption but you’ll want to allow onion plants to fully mature if you plan on storing them.

If you are curious about how large those onions are under the ground, you can get a good idea by looking at the leaves. Each hollow leafy stalk coincides with a ring layer of an onion, so you can examine the leaves to give you a hint to the growth of your onion plants.

Onions should be harvested in late summer, prior to the onset of cool weather to prevent spoilage or damage from the direct sun. Bulb onions should be harvested approximately 100 to 125 days after planting. Unlike the green onions, bulb onions will communicate with you and let you know when they are ready for picking.

The telltale harvest sign is when the stalks turn yellowish or brown, dry out a bit, and topple over. Once you see this happen, plan for an early morning harvest when temperatures are milder. Use a pitch forth and loosen the soil around the onion stalks, then gently pull the onions up out of the ground by the stalks.

Recommended Varieties

‘Candy’ is a reliable day-neutral variety that has a crisp, mild taste and thin papery skin.

‘Patterson’ is a trusty storage onion that has a more pungent taste than most onions, but the last the test of time when it comes to storage.  It is a high-yielding producer of golden yellow 4-inch bulbs.

‘Southport Red Globe’ are a gorgeous reddish-purple onion variety that produces high yields in Northern climates.

Storing your Storage Onion Harvest

Hopefully, you have harvested a healthy bounty of onions.  All is for naught if you don’t know how to store them properly. Onions require a drying process before they can be successfully stored.

After harvest, allow them to lay on the dry land for a few days out of direct sunlight. Then bring them in and lay them out on a dry, flat surface that has good airflow and cooler temperatures, and is free from direct sunlight.

They should be left untouched for about three weeks until the stalks are completely dried out and the outer layers of the onion are crisp and dry. After the drying process is complete, you can snip off the stem within one inch of the bulb, and the roots can be trimmed back as well.

Store your cured onions in a crate, netted bag, or in a wire basket and store in a cool environment with low moisture levels. Here, they will keep for up to three months if stored in proper conditions.

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