Walking onions are a unique perennial plant that offers a continuous harvest of three distinct edible parts. They propagate through small bulb clusters called bulbils, or topsets, which form at the top of the flower stalk. The common name comes from the weight of these bulbils, which eventually causes the stalk to bend over and root into the soil, starting a new plant a short distance away. This self-propagating characteristic makes the walking onion a dependable, low-maintenance addition to any garden.
When to Harvest Different Parts
The green tops, which function like scallions or chives, can be harvested almost continuously from early spring onward. This “cut and come again” approach allows for a steady supply of fresh greens throughout the growing season.
Underground bulbs, which are smaller than standard onions, are typically ready for harvest in the late summer or early fall. The visual cue for their maturity is similar to that of other onions: the green leaves will begin to yellow, weaken, and naturally flop over. This indicates that the plant has directed its energy to bulb development.
Aerial bulbils, the plant’s unique reproductive topsets, mature from mid-summer into the fall. They are ready to be collected when the supporting stalk has bent over and the bulbils feel firm with a slightly papery, dry skin. Harvesting the bulbils at this stage ensures they are mature enough for culinary use or successful propagation.
Harvesting the Greens and Underground Bulbs
When harvesting the greens, use sharp scissors or a knife to snip the hollow leaves from the clump, leaving at least a few inches of green growth behind. This method prevents injury to the plant’s base, allowing it to regenerate new leaves for a later harvest.
Harvesting the underground multiplier bulbs is generally a one-time, terminal harvest for that specific clump. In late summer, use a garden fork to gently loosen the soil around the base, taking care not to puncture the bulbs. Lift the entire clump from the ground and separate the individual bulbs.
While removing the whole clump sacrifices the mother plant, walking onions multiply at the base. Dividing the cluster during harvest allows for replanting. You can replant the smaller side-bulbs immediately to ensure continuous production for the following year.
Collecting and Replanting Aerial Bulbils
The bulbils are collected once the stalks have bent over, or just before they are about to touch the ground. You can simply snap off the entire stalk or use shears to cut it cleanly near the top of the main stem. Once the stalks are removed, the clusters of individual bulbils can be easily separated from the dried, papery casing.
These topsets can be replanted immediately to establish new plants. Plant the bulbils shallowly, about one to two inches deep, with the pointed end facing upward. Spacing them four to ten inches apart will give the new plants adequate room to develop robust root systems.
The bulbils can also be used in the kitchen. Their flavor is often described as more pungent and intense than the green tops, making them suitable for pickling or roasting like pearl onions. For consumption, the bulbils are best harvested when they are fully formed but before they show signs of sprouting.
Storing Your Walking Onion Harvest
Freshly cut greens will only keep for a short time and should be stored in the refrigerator, often wrapped in a damp paper towel or placed in a plastic bag. For longer storage, the greens can be chopped and frozen for use in cooked dishes.
The underground bulbs require a curing period similar to standard onions to maximize their shelf life. After harvest, allow the bulbs to dry in a warm, well-ventilated, and shaded area for approximately two to three weeks until the necks are completely dry and the outer skin is papery. Once cured, store them in a cool, dark, and dry location, like a cellar or pantry, where they can last for several months.
If the aerial bulbils are not replanted right away, they should be cured for a few days in a dry, airy place to prevent mold and rot. Store the dormant bulbils in a cool, dry, and dark environment, such as a mesh bag or open container, until they are planted in the fall or the following spring.