Depends on where they have come from. If they have been hardened off outside on a garden centre beds they should be ok. If you don't know their history, they might have been kept in a glass house or grown in a heated environment so just put them outside in the daytime when the temperature has risen for a couple of weeks just to be on the safe side.

I agree it depends where they have been during this cold snowy spell. if the are in pots then I'd be tempted to wait until the soil warms up a bit and dries out a bit too.

Thank You for your info, I was asking for a friend who bought them in Tesco’s, she is going to do as you advised x

I suspect that they have been indoors in which case she needs to get them used to the cold. so outside during the day unless very cold and back inside at night . do this for 2 weeks or so then they can go in the ground , unless frozen of course.