I plant onion sets only to harvest green onions. If I were to leave them in the ground, I will end up with a cooking onion after the bulb is full and the tops have fallen over in the fall. The original set will have disappeared unlike when you pull up a scallion and find the original planted set mushy.

So these things I planted will not become full size bulbs? Is that what you are saying?

I think she said the onion WILL bulb and become a full size onion. Only the original "set" will dissapear.

I thought the set would turn into the bulb - so I guess I was wrong. But the parts of mine I can see are now turning into "real" onions.

If you can keep them from bolting, they will be full size onions. Bear in mind tho, that these cultivars are all long term storage onions and long day onions. They do not attain the size of the modern sweet onions. They need to be ready to start bulbing around the summer solstice. As mature onions they will be pungent and are better for cooking then fresh use. They will store all winter.

If you are after large sweet onions like the Vidalia type or Walla Walla or Sweet Spanish, you must buy the plants. The tiny things that look like grass or chives. You may also plant seeds early indoors. You may harvest early before they start to bulb and eat them like scallions. I like this type when it's just starting to bulb. Like, maybe the size of a large marble.

My yellow onions that I am growing from set have begun bulbing. So, yes, as others have said they will bulb.

shirleywny5: "Vidalia type" (Granex) will not grow into bulbs in MA because they are short day onions.

Jon

Bomber,
Sets produce just fine for both green and storage. I don't like to buy the bagged variety--unless just for green onions. My personal experience has taught me to buy in bulk and choose the tiniest sets possible. They produce the best bulbs while the larger sets make the best green onions. I also store spring-bought sets in my fridge for fall. Plant in late Aug/early Sept for some great fall green onions. Store in a paper bag though.

Brook

I planted sets (savannah sweets) with the intention of using them as green onions. I thought I would have a nice steady supply. Mine have all bulbed. We don't have basements here so I have nowhere to store the onions. They are still in the ground but I think I am supposed to dig them up before they rot. I can only eat so many onions at a time.

margocostas: Harvest the bulbs, peel and chop and toss them in the freezer! They are great all winter for cooking.
Just knock the bag on the counter and pour out what you need. Re-freeze the bag. No need to thaw.
They really don't take much freezer space for the amount of onion you have to use later!

Deanna

Where do bulbs come from in the first place? Onions dont make bulbs, Onions are biennials and they are grown from seed. On the second year the onion if left in the ground will bolt and produce a flower to make seeds. (Just like carrots)..
So where exactly do these bulbs come from???

They're nothing more than immature onions, probably seed started.

"onions don't make bulbs". There is some serious confusion going on! Obviously, onions do make bulbs. What sort of bulb depends on the sort of onion.

The sort of onion discussed here is the so-called "spanish" onion, which is adapted to be propagated by seed and to the latitude of southern europe (it also does well at higher latitudes). And the so-called "bermuda", which is a variant of the same adapted centuries ago to the low latitudes. Crossing those two has created the so-called "short-day" type. All of these are best propagated by seed. Using little first-season mini-bulbs (created by growing in crowded conditions) is an inferior short-cut, though involving much less trouble. There is much bolting,not surprisingly, and those that don't bolt don't produce as big a bulb as a seed-grown plant would.

Outside the typical spanish-type "bulbing onion" is a bewildering world of edible alliums, where even the meaning of the term "onion" is hard to define. I have a top-setting clonal allium with flat leaves (like garlic) but a very mild sweet-onion taste. The clonal top-setting family is immense and diverse and clearly linked to the garlics. Then there are the "multipliers", potato types and shallots, which produce true seed and seem intermediate between top-setters and the hyper-cultivated spanish family. And let us not forget leeks......

I planted onion sets this year. The little round marble-size bulbs. I planted them because I found them sold loose by the pound at a Mennonite market I visited, and the plant-type sets I can only find in bundles of 50 or so. I have a 4x8 garden, with no room for the bundles.

Also, I thought that if I planted the bulb-sets a few at a time, two weeks or so apart, I'd get onions maturing two weeks apart. That seems to be working! I'd once been told it wouldn't, but the first ones I planted are bigger and starting to bulb, the last ones barely green-onion sized now. The ones planted between are in the middle of maturity, just like I'd hoped.

My question now is, will the plant-set ones work the same way? Or, because they are already "plants" will they not keep like the bulb-sets did?