I would like to experiment on growing onions form an onion, instead of buying each year seeds, sets or little plants.

I heard that planting one onion does not immediately gives more onions. Opposite to shallots, which apparently you can plant and you'll get a bunch of shallots instead. And for leek you can do the same.

So my question is more or less what is the life cycle of an onion? Can I plant my onion, where from I'll get a plant and seeds, which I can use next year? Do I need several plants or are both sexes present on one plant?

On the question: Onion seeds v. onion sets I read onion seeds are perishable. So if I harvest them this summer I should immediately start them again (in little breeding pots)? But you should only plant onions right after winter? Can I dry them and use them for the first coming season?

  • I've always heard regular onions are biennials. However, I planted some full-grown onions once and the one or two that survived our weather until the next year went to seed, as expected, but when I dug it up, I found that it had divided into three smaller onions (which I ate). I'm not sure if they would have kept growing into future years had I nurtured them, or if the fact that they went to seed means they wouldn't grow anymore (there didn't appear to be anywhere for new leaves to grow). It just had seed stalks. Apr 12, 2017 at 3:49
  • You might be interested in the Green Mountain multiplier onion or the Yellow potato onion. They're supposed to be perennials, similar to shallots; same for bunching onions. Apr 12, 2017 at 4:09

2 Answers 2


The onions are planted from bulb to early April, the distance of planting should be 10-15 cm from plant to plant, and 15-20 cm between rows, each bulb will grow from a single onion.

The harvest of onions is from August to September when the leaves turn yellow and bend on the ground, once removed from the ground onions can be left on the ground to dry them and Keep them clean them before.

Plant an onion (possibly a bit grown with small leaves on it), and wait. Onion divides itself and creates multiples plants in one. Get it in autumn and separe it. Keep one of them to moltiplicate.

Alternatively, you can cut a big onion, with multiples bulbs, with a shape knife, at the base. The fust is the plate lentille between roots and leaves. Cut carefully it in 3-4 parts, paying attention to let some roots to any piece, let them dry (some days) and plant. Be careful with watering, since the plant is "wound".

You can leave your plants into the ground years. Each year you harvest what you need. Flowers are very nice, though smell.

Some plants do "very little onions", that can be planted as bulb. (bulbilli) bulbilli
(source: inorto.org)
(source: inorto.org)

They are not seeds but little bulbs. Just pull the cloves from the mother plant and bury, they can spend the winter in the open field, because they aren't frost sensitive and are resistant to many diseases. They are known also as Egyptian onion, tree onion or onion walking.

Alternatively, you can grow then from seeds but its very hard, as you know.

see seeds

Below, many onions in one before harvesting and didviding = you can see the young bulbs under old skin cip

In my experience.

  • Growing bunching onions from seed is pretty easy, at least. Even if you start late, you can just wait until the next year before you start harvesting any. I direct-seeded a bunch of Crimson Forest seeds from Reimer Seeds in May, June (really late for onions) or so last year; they germinated well in partially shaded clay soil, in a raised bed, and they're looking good (if in need of thinning) this year. The regular Southport Globe Red onions from another store didn't germinate beside them. I got some garlic chives to germinate by them, though, but the rates weren't as great. Apr 12, 2017 at 4:03

The onions that I know to produce "top sets" are called Egyptian ( look just like the picture in the other answer). They can be invasive. They wintered-over in the Chicago area. However , I find them to be very exceptionally strongly flavored , even cooked: And I like onions.

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