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Does anyone grow heat treated onion sets in place off or with ordinary sets and how do they compare?

The only reason they appear to be superior according to the catalogues,is that they are less likely to bolt, and usually I don't find this a great problem, except with the red varieties!

Having only ever grow ordinary ordinary sets I would appreciate others experiences!

Also how is it with onions sown from seed, do they bolt or store as well as ordinary or heat treated sets?

Others in our gardening club only grow from seed or from normal sets,they think heat treated ones are too expensive and also they are not available untill April, when the others are already growing well!

Cheers!

Heat treated sets take a lot of uncertainty out of growing onions. They are less likely to bolt, but this is not altogether eliminated. They are available late in the planting season because the heat treatment is more accurately a warmth treatment, which needs to be over a long period. Planting into a warm soil reduces the likelihood of an onion set to bolt in any case, so early plantings are not always advantageous.

Growing from seed is straightforward but it is an extra step, in terms of raising transplants which can be fiddly: onion sets are a convenient and quick unit to plant. From seed, bolting is no more or less likely.

Red onions are a nightmare for the plant breeder because they have always been so much more prone to bolt, and it is why they remain expensive. In my view, they are best avoided. Blind tastings have shown them to be indistinguishable from the brown sort. They look nice on the plate, though, if that is so important. But when cooked, they turn a sort of grey. Overrated.

We've grown heat treated sets before and had good success - if any bolting has occurred it is only on one or two bulbs.

Heat treated bulbs are sent out a little later as they need time to complete the heat treatment process which should kill the immature flower bud which is why they shouldn't bolt.

I've tried them all and find the ones from seed perform best and don't tend to run to seed. Heat treated are a bit less likely to run to seed than ordinary sets, but if you haven't much time or have forgotten to sow the seeds early enough a bag or two of sets usually provide plenty of nice onions.

One advantage of growing from seed, you have a lot more choice of varieties. My favourite is Ailsa Craig which always performs well and is a nice flavour and good keeper.

I've gone off the red onions as they are usually tough, strong tasting, run to seed more, and go an unattractive grey colour when you cook them.

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Thanks for all you answers, will give them a miss from your replies!


Reguarding size, me I want to grow them the size of footballs (some hope) my wife wants them the size of tennis ball or smaller!

Cheers!

Must admit this surprised me as we only ever have occasional heat treated sets bolt when we used to get lots of the none heat treated ones. We wouldn't keep buying at the extra cost if it didn't work.

I wonder if it depends on who you buy them from if heat treating kills the flower bud as it is supposed to then the onion can't bolt surely so the odd ones that do will just be the ones where the flower bud survives.

We buy the nets of sets from Wilkinsons, which aren't heat treated and don't have a problem with bolting. The odd one or two go a bit daft but not enough to worry about. They grow well, taste good and keep well too.