"Ed" wrote
I've just got my onion sets for autumn planting and garlic which I'm
intending to plant out in the next couple of weeks.


Oh dear, see my comments under "Complete Newbie to veg growing".

Never done these before , so:

Do these need netting to protect against birds, as do spring planted
bulbs?

We have never netted any onions, ever. Cabbages yes, onions no.


Do I need to cover them with fleece overwinter? Somehow, I doubt if I need
to do this as they are supposed to be winter hardy.

Certainly not, the garlic needs a cold spell to grow properly and is so
tough it will grow in any warmer spell we get during the winter.

I welcome advice from experienced growers.

(I'm in Herts, SE UK)



--
Regards
Bob Hobden