Planting, caring for and harvesting multiple onions

The layer or aerial onion is rarely found. However, with its striking appearance, versatile plant parts and easy care, it is an asset to any garden.

The tiered onion (Allium x proliferum or Allium cepa var. viviparum) is a bit strange to look at: the small onions do not form underground, but above ground on stems, where they sprout directly and thus form several "tiers". The tier onion owes its name to this fact. But the air onion doesn't just have a lot to offer visually. Parts of the plant can also be used in the kitchen almost all year round. In this article you will learn everything about growing bunch onions, from planting to harvesting and use.

Bunch onion: origin and properties

The tier onion, also called aerial or Egyptian onion, is a rather unknown representative of the genus

Allium. The onion species, which probably originally came from Siberia, is also hardy here and even evergreen in mild winters. Then the round, hollow leaves of aerial onions can be harvested all year round. The plants can grow up to 80 cm high and form small bulblets instead of flowers from June to September. It is not uncommon for these to sprout on the stem and thus form a second, sometimes even a third tier. As summer draws to a close, the stalks break off and the bulbs sink to the ground. There they root and thus ensure the propagation of the mother plant. This is also reflected in one of the Latin names: „viviparousm” roughly means “live-bearing”.

Planting a bunch of onions

Tiered bulb plants can be purchased at specialty stores. However, the small spring onions are often passed on from gardener to gardener. Bunch onions cannot be grown from seed, as the plant does not flower and therefore does not produce seed.

Bunch onions are weak consumers and have very low demands on the location. They prefer sunny to semi-shady locations on calcareous, humus-rich and loose soil with a pH above 6.5.

Important: Keep a cultivation break of at least 4 years between planting the tiered onion and others Leek crops such as onion, leek and spring onion, otherwise it can cause crop rotation diseases come.

You can also grow air bulbs in a pot with a volume of 10 liters or more. For this we recommend our Plantura organic tomato & vegetable soil, as it has a fluffy structure and high levels of potassium – both important for healthy, aromatic bulb plants. In addition, the soil is peat-free and is sustainably produced in Germany. The soil should be thinned out by adding 30% sand, which also ensures better water drainage. The best time to plant tier onions is either in late summer from August.

Planting bulbs step by step:

• Prepare the soil of the bed well by clearing it of weeds and loosening it up with hoeing.
• Soils in our regions naturally acidify over time. For example, one factor that enhances this natural process is fertilization. Therefore it can be helpful to use some lime, like ours, before planting Plantura Organic Lawn & Garden Limeto work into the ground. If you are unsure whether liming is necessary, you should first Determine the pH of your soil.
• Place the onions 30 - 40 cm apart on the ground and press the onions lightly. Alternatively, you can plant the bulbs about 5 cm deep in the ground.
• In the following period it is important to ensure that the soil does not dry out. But it should never be too wet around the onion, because then it can happen that the onion begins to rot and does not sprout.

Tip: It is best to plant onions that have not yet sprouted and look healthy. This increases the chances of good growth.

The right care

Bunch onions are easy to care for. Like all onions, they are weak consumers and usually do not require fertilizer. You should be particularly careful with fertilizers that emphasize nitrogen: Too much nitrogen increases vegetative growth, among other things, so less onion mass is formed. If necessary, however, a fertilizer containing potash can be applied in the spring. Potassium is also an important plant nutrient, which plays an important role in the water balance, for example, and makes the plants more stable, disease-resistant and frost-resistant.
Air onions only need to be watered during longer periods of drought.
Especially at the beginning of growth, it may still be necessary to remove weeds from time to time around the growing onion plants.

Tip: Old and withered foliage can be removed periodically to make room for new stems. An important pest of the bunch onion is the onion fly (Delia antiqua), the larvae feed on the underground plant parts. This can cause the chimneys to become unstable and buckle. They should remove infested plants and think about a new location for the tier onions.

Multiply tier onions

In nature, stage onions reproduce via the brood bulbs that sit on the stems of the plant. At some point the weight of the small onions is so high that the stalk snaps and the onions sink to the ground. There they root, sprout and form new plants.
Since the tier onion does not form flowers or seeds, it can only be propagated vegetatively - either by dividing the mother onion or via the brood onions. You can simply let nature take its course and let the plant multiply itself, or you can harvest the bulbs and put them in the ground yourself. August is the best time to do this, when the onions are ripe and strong.
Another method of propagating tier onions is by dividing the mother bulb. In the course of storing reserve substances, the plant forms several secondary bulbs. These can also be dug up in autumn and planted individually in new locations.

Are air bulbs hardy?

Bunch onions are hardy and perennial. This means that they survive the winter well in the bed and will sprout again in the new year. If the winter is mild, the plant stays green and you can continue to harvest the stalks.
If you have grown the multi-onion in a pot, however, it should be protected from frost by insulating it and placing it out of the wind.

Harvest and use stage onions

All parts of the plant of the aerial onion are edible. Both the brood onions, the green chimneys, and the mother onions in the ground. This means that some of the tier onion can be used almost all year round. The green chimneys should not be harvested excessively, especially if the plant is still to develop onions. The onions formed between June and September can be harvested as soon as they have reached the desired size. Only in autumn, from the end of September, can the remaining onions be harvested and used directly or stored. These can be stored under suitable conditions – i.e. cool, dark and above all very dry – until next spring. However, only onions that have not yet sprouted are suitable for this.

In the kitchen, the brood onions of the tier onion can be used in many ways, but are suitable due to Because of their size, they are excellent for pickling as silver onions, but also raw, fried or as onion spice. Their taste is described as finely aromatic, hot and oniony, so aerial onions are also often used in pasta or as an accompaniment to meat and fish.
The green chimneys are ideal as a substitute for chives or spring onions. In terms of the ingredients, stage onions are in no way inferior to ordinary onions. Due to the essential oils, the use of onions can have a positive effect on vascular diseases such as arteriosclerosis and high blood pressure.

Summary: Harvesting and Using Bunch Onions

• All parts of the tier onion can be used in the kitchen
• Harvest the chimneys all year round from the moment they sprout and use them like spring onions or chives
• Onions ready for harvest from July, from the end of September they can be harvested for storage. The onions can be used whole and pickled, fried or eaten raw in a salad.

Tip: We recommend not removing all the bulbils on a chimney in summer, but leaving a few on the plant, which may then form a next tier.

Are you a friend of unusual vegetables and like to experiment in your garden? Then we can give you our article about strange vegetables recommend.