[stompy]

Sets are relatively cheap easy to grow, high success rate and there's quite a good selection of varieties?

So what if any are the advantages of growing onions from seed over sets?

[Kleftiwallah]

Can be grown overwinter in a greenhouse with heating and lighting getting a good start to the season.     These onions (if a good variety) will grow much larger.   

Also a lot less chance of seed onions running to seed.   A larger choice of varieties in seed rather than set.      Cheers,     Tony.

[JayG]

If my experience this year is anything to go by growing onions from seeds provides an extremely extended opportunity to improve one's patience skills (and possibly some quite big onions in time for Christmas!) 

[stompy]

so it's down to Size at the end and a better range of varieties?

[mumofstig]

With seed there is no chance of importing onion basal rot -  slightly different to onion white rot, but still rots the base of the bulbs







edit to clarify

[TerryB]

As all the others have said but also for anyone suffering from allotment withdrawal symptoms, you can plant them from Boxing Day onwards.

[stompy]

There is no chance of importing onion basal rot -  slightly different to onion white rot, but still rots the base of the bulbs

I thought all sets were certified as virus free?

also for anyone suffering from allotment withdrawal symptoms, you can plant them from Boxing Day onwards.

  

[Trillium]

I prefer seeds mostly for the variety I can get rather than limited variety from sets. Also, I rarely have as good luck with sets as I do with seeds which can keep growing rather than halt growth for set harvesting.  If I start seeds right after Christmas, they're a good size by planting out time (April for me).

[New shoot]

I tried seed the last couple of years as well as sets and have decided just to go for sets next year as the seeds seemed a lot of faff and I have heavy soil which they don't seem to like being transplanted into.  Sets seem better able to cope and just get on with it.

After reading various threads on the subject on here, I started my shallots and onion sets in cell trays this year and it really paid off.  Bit of a fiddle if you are doing lots but I just do shallots to pickle and then some red onions for salads  

[hightide]

We love onions and I have always gone with sets as I have never been able to successfully grow onions from seed, except for one memorable year with Bannana Shallots. This year has been an eye opener and a complete reversal; all the overwintered onions failed, even the garlic, and the summer onion sets stopped growing when they were not much bigger than the planted sets. I do have twelve absolutely gorgeous Red Baron onions still growing and also eight good sized Ailsa Craig, which were grown from seed.
 
I think the weather this year has had a lot to do with it as I have never had such a good crop of spring onions, ever. Some of them are nearly as big as the sets, I just can't eat them quick enough. I will remember 2011 as the year of the seed as the seed sown onion seemed to cope better with the contrary conditions this year. This experience is encouraging, their excellent condition has convinced me to try to sow more onions from seed.
 

[Robert_S]

I tried a few from sets this year in the garden...they were nearly all quite disappointing despite many having good top growth...still edible though.   Now having the allotment, I will be trying every which way...autumn grown from sets, from seeds and spring planted sets. The more the merrier

[shokkyy]

In prior years I've always done sets, always got a decent crop but the onions were always fairly small. This year, for the first time, I grew Ailsa Craig and Bedfordshire Champion from seed. They had me worried for a few months because they're the slowest growing seedlings I've ever done, but in the end they're sitting on the surface looking smug, twice as big as any onion I've ever grown from sets. There's a few tiddlers, but most of them are a very decent size, and some are very big indeed. Time will tell how well they store, but once they were planted out I pretty much ignored them apart from watering now and then.

[Babstreefern]

I've grown both sets and seeds, and I definitely prefer growing from seed.  They're cheaper for a start and you've loads of choice whether by size or colour.  This year, I've grew Mammoth Reds and the white onions are Kelseys - really huge.   

I grew my shallots from sets this year, but I'll have a go at using seeds next year.  I didn't get many sets and for the price I paid so I'll definitely try seed next year.

[Nobbie]

Interesting that many are saying they get bigger onions with seed, but I find my sets have been huge the last two years (Sturon and Turbo). To be honest they're a little too big as I won't need a whole one for many meals. I might try some reds from seed as they always seem to bolt from sets.

[Yorkie]

Interesting that many are saying they get bigger onions with seed, but I find my sets have been huge the last two years (Sturon and Turbo). To be honest they're a little too big as I won't need a whole one for many meals. I might try some reds from seed as they always seem to bolt from sets.

My onions in the front garden from sets are huge.  I've started using only half in my cooking (unless making a big stew or something); and keep the other half in one of these:
http://www.lakeland.co.uk/9238/Half-of-One