You need to start the seed off in March/April. I expect Geoff Hamilton's technique with onion seeds sown thinly in modules and then planted out in their little clusters without thinning would work well.
Have a look on YouTube for zebrune shallots there are some good videos on there showing seed sowing through to harvest although zebrune don't split like a normal shallot more of a shallot onion cross that's highly regarded by chefs
I always grow my shallots and onions from sets rather than seeds. They have always grown well on my allotment. I planted some onion sets in mid-October straight into the ground, alongside garlic which I planted a few weeks later. Both have germinated, so I'm hopeful of an early crop in late Spring.
Well, @garyoneill65, if you read the first post you'll realise @GWRS couldn't find sets so has bought seeds and was seeking advice as he usually grows from sets.
I have only ever done onions from seed and did them in small clumps, as advised by Geoff H years ago on GW, and I don't expect shallots from seed are much different. Now I'm in an area that doesn't freeze solid in winter I'm trying shallots from sets for the first time this year after doing very well with garlic.
"We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
Thank you for your response @Obelixx. My first day on the forum, so I've learned to look back at the thread rather than respond to the latest post! Apologies
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This is what the RHS says - https://www.rhs.org.uk/advice/grow-your-own/vegetables/shallots
I have only ever done onions from seed and did them in small clumps, as advised by Geoff H years ago on GW, and I don't expect shallots from seed are much different. Now I'm in an area that doesn't freeze solid in winter I'm trying shallots from sets for the first time this year after doing very well with garlic.