This year's pot display next year's garden

Hi Guys hope the sun is shining wherever you are. Planning our pots and troughs for the summer we need to empty them first. At the moment they have spent tete a tete and heritage primroses (which are still giving a lovely display) I've cut off all the seed heads so the bulbs don't use up energy making seeds. What is the best fertilizer to use and should I replant them in the garden or dry them as for the primroses plants should I remove them before feeding