Winter Onions

Bought some  winter onion plug plants today from aldi as I've never grown them before which is the best month to plant them? They are snowball variety

That's odd; the variety sold in our Aldi is Tuffball.  Must be regional differences in what they are selling.

It is a bit early as the seeds usually say to sow in August, but if you bung them in and they get to a decent size you can always eat them as giant spring onions in the autumn.

Hardly any of my overwintered onions make it to maturity as I scoff the lot each spring as soon as they are big enough to be worth pulling up