A green shoot doesn’t, by itself, mean an onion bulb has spoiled. Purdue Extension says firm flesh can still be used after sprouting, although the onion deteriorates more quickly.
Check the bulb before using it. Discard it if you find mold, mushy or slimy decay, or a rotten smell. Don’t judge the onion by the length of its shoot, and don’t assume that cutting off the shoot makes a spoiled bulb usable.
Before peeling or cutting an onion, rinse it under running water and use clean utensils. Washing reduces bacteria, but it doesn’t remove all of them. Refrigerate cut or peeled onion promptly in a covered container at 40°F (4°C) or below.
9 Types of Onions That Can Sprout
Stored bulb onions can resume growing after a period of dormancy. The variety, temperature, and other storage conditions affect how well they keep.
Store whole dry bulbs somewhere cool and dry with good airflow. Some sweet onions keep better in the refrigerator, but cold storage doesn’t stop them from deteriorating.
Planting a mature sprouted bulb isn’t a reliable way to get a new crop of full-size onions. UNH Extension explains that these onions are likely to flower as they continue their life cycle.
Welsh onions and shallots grow differently. Welsh onions don’t form large rounded bulbs, while shallots can be propagated by planting individual bulb divisions.
With those differences in mind, here are nine onion types that can develop new growth.
1. Bermuda Onions
Bermuda onions have flattened bulbs and can have yellow or white skins. They’re known for their mild flavor.
These onions generally don’t keep as well as varieties grown for long storage.
Bermuda onions can sprout during storage.
2. Walla Walla Onions
Commercial Walla Walla Sweet Onions come from a defined area of southeastern Washington and northeastern Oregon. Walla Walla seeds and transplants can also be grown in suitable gardens elsewhere.
These onions can grow large and have juicy, mild-flavored flesh that works well in raw dishes.
Like other sweet onions, Walla Walla onions are generally better for fresh use than long storage.
3. Welsh Onions
Welsh onions (Allium fistulosum) are perennial bunching onions. They grow in clumps and don’t form the large, rounded storage bulbs that common onions do.
You can use their green leaves and white lower stalks in soups, salads, and other dishes. They’re often called spring onions or scallions, although these names can also refer to young bulb onions.
Established Welsh onion plants can produce creamy-white flowers in summer.
4. White Onions
White onions include several varieties with different flavors and keeping qualities.
For instance, these onions find wide use in Mexican cuisine. They’re used both in the raw and cooked form.
They form a great addition to salsas, salads, taco fillings, chutneys, and stews.
How well they store depends on the variety, proper curing, and storage conditions. White skin alone doesn’t tell you how long an onion will keep.
White onions can also sprout during storage.
5. White Grano Onions
White Grano onions have white skins and flesh.
Thresh Seed Co. describes its White Grano onions as mild and suitable for salads, although pungency descriptions vary between suppliers.
White Grano is a short-day onion, so it is usually better suited to growing in the southern United States.
6. Candy Onions
Candy onions are large hybrid onions with a slightly flattened shape and yellow outer skins.
The flesh is juicy, white, and firm. These onions are crispy and sweet.
Their sweet flavor makes them useful raw or cooked.
Curing freshly harvested Candy onions helps them keep longer in storage, but it doesn’t prevent sprouting or spoilage indefinitely.
Candy onions can develop shoots and roots during storage.
7. Vidalia Onions
Vidalia onions are known for their sweet, mild flavor. The name applies to approved Yellow Granex varieties grown in a defined region of Georgia.
Their flavor depends on the variety and growing conditions, so sweetness and pungency can vary.
Vidalia onions bruise and spoil more readily than dry-storage onions, so handle them gently and use them before they lose quality.
8. Shallots
Shallots are close relatives of bulb onions, and many belong to Allium cepa Aggregatum Group.
They have similar flavors and resemble onions but are smaller.
Their skin and flesh colors vary. Some have reddish-brown skins and white flesh, while gray-skinned types also exist.
They may be rounded, teardrop-shaped, or elongated, depending on the variety.
They’re widely used for pickling. They’re also good for cooking.
Shallots have an onion-like flavor, which can be milder and sweeter than that of many bulb onions.
Whole, well-dried shallots can keep for several months in a cool, dry, well-ventilated place. They can still sprout when storage conditions favor new growth.
9. Texas Super Sweet Onions
Texas Super Sweet usually refers to the 1015Y variety, also called Texas Grano 1015Y. It is a different onion from Yellow Granex.
These onions have rounded, globe-shaped bulbs with yellow skin and white flesh. They’re known for their sweet, mild flavor.
You can eat them raw or use them for cooking.
Texas sweet onions can also sprout during storage.
