"Byard Sheppard" wrote in
message ...

My wife bought some bulbs while on holiday in the UK, now on her return
to Vietnam she has been told that she must Vernalise them or they won't
flower.

That would make sense. IIRC you live near/in Hanoi? Rather different
climate round Hanoi to anything the UK has to offer.

A quick ask around the bar came up with nothing positive on method,
other than bunging them in the fridge for a week or two.
Is there a time of year when this should be done and for how long, at
what temp is the freezer too cold.

Any 'freezer' will be way too cold and will just kill the bulbs. The
crisper section of the fridge is the place to put them (in a paper bag).
Time in the fridge will depend on the type of bulbs.