Posted: 19/10/2017 at 16:05
Depends whereabouts you are and how sheltered your Cold frames are.
If you gradually acclimatise your hardy perennial plantlets to the cold frame, they should see the winter through and then be ready to plant out in Spring.
I think you are probably right about your geranium cuttings ( unless you are talking about Geraniums rather than Pelargoniums )
I tend to use mine for perennials which have been sown late summer/autumn and also for sowing other seeds which like a cool/cold spell before they germinate in the spring. Cuttings of hardy/half hardy plants which have rooted but too small to plant out also go in the frame.
Again, think about your particular climate and the aspect. You can of course add further protection to plants you are a bit "iffy" about - newspaper or fleece - just in case. Remember tho that whatever you put in there will still require some ventillation at some point through the winter months.