it depends what plants they are? spend a couple of weeks hardening off so they can acclimatise, then plant them out when the risk of frost is over. just don't plant them out too early.
I have already planted out my early potatoes,Onions,and shallots and yesterday I put in carrots,parsnip,Radish,Rocket,Beetroot,In my greenhouses which is kept heated at night I have Runner Beans and french Beans which I'm contenplating putting out next week, I also have just pricked out sweet peppers you could plant peppers,tomatoes if you don't have a greenhouse site them on a windowsill hope this is of help
I have some tomato plants ready to plant out and have already put out my potatoes too. It's the runner beans I'm not sure about so i'll take your advice and wait another week or too. Thanks