Onions are a common vegetable found in many kitchens. They add great flavor to dishes and can be eaten raw or cooked. As an onion matures, it will eventually send up a stalk and produce flowers. This is a natural stage of the onion’s life cycle. However, once an onion flowers, it raises the question – can you still eat onions that have flowered? Let’s take a detailed look at what happens when onions flower and whether it’s still safe to eat them.
What happens when an onion flowers?
Onions are biennial plants, meaning they take two years to complete their life cycle. In the first year, the onion plant produces bulbs and leaves. If the bulb is left in the ground over winter, it will use the stored energy to send up a tall stalk and produce flowers in the second year.
The flowering stalk emerges from the center of the bulb and can grow 2-4 feet tall. At the top of the stalk, a cluster of small white, pink, or purple flowers develop. This is the onion plant reproducing by spreading pollen so it can produce seeds.
As energy goes into producing flowers and seeds, it takes away energy from growing the edible bulb. This is why onions that have sent up a flower stalk will have a tough, woody texture when you cut into them. The quality and flavor also deteriorates once the onion starts flowering.
Are flowered onions safe to eat?
While onions that have flowered won’t have quite the same texture and flavor as onions harvested earlier, they are still safe to eat.
Some key points on eating flowered onions:
Onion bulbs are edible before and during flowering
The onion bulb that formed the year before will remain edible as the plant flowers. Although texture and flavor decline, the bulbs don’t contain any toxic compounds or become poisonous.
You can chop up and use the onion whites and greens until they start to dry out. Onion bulbs will eventually get woodier and drier as the plant directs energy to flowering.
You can eat the onion stalks
The new growth that emerges from the center of the bulb and produces the flower stalk can also be eaten. It’s often referred to as a scape.
The scapes have a mild, sweet onion flavor. They can be used raw in salads, cooked in soups and stews, pickled, or grilled. Snipping off the scapes can actually promote better bulb growth below ground.
Avoid eating the flowers and seeds
While the flowers themselves are not toxic, they tend to have a tough, unpleasant texture. The flowers open to reveal small black onion seeds. These packets of seeds are also not typically eaten.
It’s best to remove the flower head and use the young, tender stalks underneath.
| Onion Part | Edible? |
|---|---|
| Bulb | Yes |
| Leaves/greens | Yes |
| Flower stalks/scapes | Yes |
| Flowers | No |
| Seeds | No |
Changes in texture and flavor
While all parts of a flowering onion are edible, there are some important changes in texture and taste:
Texture
As flowering begins, the onion flesh becomes more fibrous and woody. This is most noticeable in the bulb, which starts to dry out and lose its juicy crunch. The leaves may also become tougher and more stringy.
The young scapes are tender and can be eaten raw or cooked. The flower stalks gradually lignify and harden, so these are best used when young and tender.
Flavor
Onion bulbs start to lose their characteristic pungency and flavor as the plant flowers. Compounds that give onions their signature bite break down over time.
The greens and scapes still have an oniony taste, but it becomes muted. There’s also more perceived sweetness as pungency decreases.
So while flowering onions won’t have quite the same robust onion flavor, they can still be incorporated into cooked dishes. The diminished taste is most noticeable when eating raw.
When to harvest onions
To get the best quality onions, they are typically harvested before flowering occurs. Some tips on harvest timing:
Spring-planted onions
Onions planted in spring are generally ready to harvest in mid-late summer when the tops start to yellow and fall over. Bulbs should be pulled up once about half the tops have tipped over. This is well before any flower stalks appear.
Overwintered onions
Bulbs left in the ground over winter can be harvested in late spring/early summer. It’s best to pull them when greens are still fresh and upright. Some gardeners will cut the tops back in fall so onions put more energy into growing bulbs rather than leaves.
Watch for flowering stalks
Keep an eye out for the distinctive tall flower stalk emerging from the center of plants. Once it appears, the plant has started redirecting energy to flowering and seed production.
Feel bulb firmness
A good indicator mature bulbs are ready for harvest is when tops soften and fall down. You can confirm by feeling the bulbs. They should be firm and fully sized.
As flowering begins, bulbs will get soft and spongy. At this point, the onion is past its prime harvesting stage.
Storage for flowered onions
Since onions start deteriorating in quality once flowering starts, they don’t store as well. Here are some tips for storage:
Use promptly
Onions that have flowered are best used immediately rather than stored. The bulbs will continue getting woodier and drying out. Flavor also declines rapidly.
Prioritize using up bulbs first before greens and stalks.
Refrigerate greens
Fresh scapes and leaves can be stored in the refrigerator for 1-2 weeks. Put them in a plastic bag or container.
They become limp at warmer temperatures. Refrigeration will prolong freshness.
Freeze for longer storage
Chop greens, scapes, and bulbs before freezing. This locks in some of the flavor and texture that would otherwise be lost.
Frozen onions can be used in cooked dishes for 6-12 months. Thaw before using.
Freezing stops the progression of toughening that happens in the fridge.
Pickle scapes
Pickling scapes in vinegar preserves them for up to a year in the refrigerator. The acidity keeps them crispy.
Use a water bath canner or refrigerator pickling to store pickled scapes.
Preserving seeds
If you want to save seeds from flowering onions, wait until the seed heads dry and turn brown. Carefully cut off entire heads and place in a paper bag. Break apart the heads to release the small black seeds.
To preserve seeds:
Air dry seeds
Spread seeds in a single layer on a screen ortray. Allow to dry at room temperature for 1-2 weeks until hard.
Freeze seeds
For long term storage, place dried seeds in an airtight container or envelope and freeze.
Test seeds for viability
Do a germination test the next season by planting a sample of seeds. This will determine what percentage sprouts. Only save seeds from vigorous plants.
Stored properly, onion seeds remain viable for 1-2 years. They can be planted in spring to grow new bulbs.
Reasons to remove flower stalks
Even if you plan to eat flowered onion bulbs, it can be beneficial to remove the flower stalks. Some reasons why:
Improve bulb growth
Snipping off flower stalks right when they first emerge redirects the plant’s energy back to the edible bulb rather than seeds. The bulbs will retain better quality.
Reduce spread of disease
Flowering makes onions more prone to neck rot fungal infections. Removing stalks reduces risk of disease spreading.
Increase storage life
Preventing seeds from forming avoids excess moisture loss from the bulbs. This keeps them firmer and juicier for longer storage.
Contain self-sown plants
Onions can aggressively self-seed if flower stalks drop seeds back into the garden. Cutting off stalks helps control unwanted onion plants the following years.
Uses for flowered onions
While flowering diminishes onion quality, their unique taste can be highlighted in certain dishes:
Cooked dishes
The mellow sweetness that develops makes flowered onions suitable for sautéing, stewing, soups, and baked dishes where onion is not the highlight.
Try them cooked into casseroles, mixed into breads and meatballs, or caramelized as a basis for sauces.
Pickling
The pungency of onions mellows during pickling. Flowered onions lend their developed sweetness to quick-pickled onion rings or other pickled products.
Homemade stocks and broths
Simmering onions into stock draws out sugars and umami flavors. Using flowered onions enhances the depth of homemade stocks without too much raw onion punch.
Compost
Once bulbs get excessively woody, dry, and fibrous, put them in the compost pile rather than eating. They still provide nutrients for soil.
Conclusion
While onions are best harvested before flowering for peak quality, you can still eat onions that have sent up a flower stalk. The bulbs, leaves, stalks, and immature flower heads remain edible, though with some decline in texture and flavor.
Onions start redirecting energy to seed production during flowering, so the bulbs become tough and woody. The onion’s signature pungency decreases. However, they can be utilized in cooked dishes, stocks, and pickling.
Use flowering onions promptly since their quality deteriorates during storage. And consider removing flower stalks to improve bulb growth and storage life if you don’t want to collect seeds.
