freezing veg

I once did that with cauliflower and it came out of the freezer looking most unappetizingly black. I always blanche any extra veg.

I had an extra cauliflower a couple of weeks ago after buying two for one. I just chopped it into flourets and bagged it and froze it. It was fine when I cooked it. I steamed it as I usually do. I know you are supposed to blanche veg then plunge in cold water. I couldn't be bothered to do that so just bagged it and froze it to save throwing it away.

Leeks and cabbage will freeze. I freeze vast quantities of vegetables and never bother with blanching. I have yet to have a problem.

The turnips, swede and leeks are fine just chopped up and frozen without blanching - they are afterall fine left in frozen ground if not picked. They are best cooked from frozen so do not defrost.
Cabbage needs blanching but only do it in a little water with maybe a knob of butter added and very quickly as cabbage doesn't need much cooking.
I don't like frozen brussels so never do them but they will need blanching.

PS Cabbage does best if frozen in chunks the size of a Brussels sprout.

In general, I follow Bags' method but for leeks or sprouts I leave them in the garden until required, sometimes picking them 'ready frozen'

I usually just chop veg that I want to freeze, give it a one minute zap in the microwave (blanching in effect), let it cool and freeze. Haven't encountered any problems with this method.

They should all freeze so long as you blanch them first.

I cook turnip swede parsnip and then bag it and freeze it. Keeps well. I would par boil brussels. Doubtful whether leeks and cabbage will freeze but they will keep in cold storage (garage)for quite a while.