Simple guide outlines how to grow green onions in water or in soil, including sowing, maintenance, and harvesting for more growth.
What is a green onion vs spring onion?
They are the same! The green onion (Allium fistulosum), also known under the names spring onion, scallions, winter hedge onion, winter onion, scotch onion or stem onion, belongs to the amaryllis family (Amaryllidaceae). In the literature, the term winter hedge onion is mostly used, but colloquially, green onion or spring onion has largely gained acceptance – even if the spring onions that you can buy in our supermarket are not always Allium fistulosum. Especially in early spring, other young onions are also occasionally (Allium cepa) offered as green onions or spring onions.
The green onion is a perennial plant that forms clumps and reaches heights of between 30 and 80 centimeters. These onions are not comparable to conventional table onions because, unlike them, they are not clearly separated from the foliage. Instead, green or spring onions have a small, white thickening at the bottom.
The aromatic leaves, which can be harvested almost all year round, are primarily used in the kitchen: dark green, hollow tubular leaves. In July, large spherical flowers, which are made up of numerous small white individual flowers, appear on thick stems, also hollow in the middle.
How to grow green onions in water
This starts with ‘regrowing’. The idea of regrowing? Instead of unnecessarily throwing away leftovers and vegetable waste or composting them, new plants can also be grown from them – namely by planting the vegetable waste. Not only does our wallet benefit, but is also an important step against food waste. Particularly great: regrowing such “kitchen waste” again is:
- not difficult at all, and…
- all you need is a window sill, a container, some water and a little patience in addition to the vegetable scraps.
Of all foods, green onions are the easiest to grow in water. When you trim off the root part of the green onions for cooking, don’t throw them away!
Put the bottom 2 to 3 centimeters with the root residue in a shallow glass of water to keep the roots moist and change the water every few days. After about a week the green will grow back and you will have fresh spring onions. Now you can plant the spring onions in a pot with soil, but this is not necessary. You can use them just as they come out of your ‘glass garden’.
Incidentally, this regrowth method also works really well with leeks and lemongrass !
How to grow them in pots or the garden
Location and soil
Green onions or spring onions thrive best in sunny and sheltered locations. The soil should be deep, loose and humus.
Crop rotation and mixed culture
Lettuce, cucumber and carrots are good partners for spring onions. Bean types, on the other hand, are not suitable for mixed cultivation with spring onions.
In order to optimally prepare the bed, rake in three to five liters of sifted ripe compost per meter. From March to May you can sow the seeds of the winter onion broadly – about an inch deep. The optimal row spacing is 20 centimeters. After emergence, you should separate the seedlings at a distance of five to eight centimeters. Further sowing is possible until mid-August. So you can re-sow gradually so that you always have fresh spring onions on hand.
Winter hedge bulbs are relatively easy to care for and the care is similar to that of chives: In addition to watering, you should regularly provide the spring onions with organic fertilizer. So that the clumps do not grow too densely and thus lose their vigor, you should dig up the perennial plants for regeneration every two to four years, divide them and put them back in the ground in a new place (see propagation).
Green onions can be propagated either by sowing them or by dividing the clumps. You can collect the black seeds, which fall out easily in summer, and let them dry out yourself. They can germinate for up to two years. Or you can share the clumps in summer. To do this, dig up the root ball of an older plant and carefully separate two to three sections with a spade. Plant them again in a new location.
The tubular leaves of the onion can be harvested not only in spring, but all year round. You can cut the leaves of the perennial winter onion like chives and they will sprout again. Or you can pull the entire plant out of the bed. Since the leaves of the spring onion wither quickly, it is best to harvest as needed.
After you have cut the tube leaves into small pieces with a sharp knife, you can sprinkle them over the dishes to refine soups, salads or quark just before serving – this way you keep their aromatic, leek-like taste. In addition, the leaves of the spring onions give cooked or steamed dishes a special touch.