I've potted on seedlings of Lupins and perennial gypsophila into individual pots and put them in cold frame. Will they die down over winter like mature plants? If yes, given they are in cold frame should I water them or are they OK to dry out?
Yes - they'll die back. They're unlikely to need any major attention, unless it's hot enough for them to dry out, and then you'd water very lightly. That would mainly be in late winter into spring though, but it'll depend on your climate and conditions.
It's a place where beautiful isn't enough of a word....
I live in west central Scotland - not where that photo is...