I planted mine? The seedlings about 6 weeks ago maybe a bit longer. Mixed results some look like they will be ready before winter. Some look like they need a winter to get moving.
I always fail to stop a few onions going to seed. The seeds come up but are to close together to produce anything more than the equivalent of spring onions
I use them as if they are sets, quite successfully. Planted some of them a week ago already on there way. They over winter okay but some don't bother growing while others are full size onions.
Alas I cocked up on the shallots I planted the large ones