I just top the containers up because the smaller bedding plants don't need as much nutrient as the larger and longer-flowering summer ones. I don't feed them, either, as lots of new growth can get frosted so easily.

Personally I would recommend all new compost, safer for the new plants. Put the spent compost on your compost heap.

Thank you Spritz and MG for your advice:)

I always put new compost in pots when planting up as the plants have a lot to do in the growing season and anything that stays in a pot - I replace the top third of the compost every spring. As the old compost is totally spent I just throw this on the garden.

Thank you Denise very helpful advice:)

Funnily enough, its not really about whether the compost is 'spent' or not, you can always correct that by adding chemical feed to it (Growmore, Vitax Q4 or similar). The problem with compost that's been in pots for a season is it may well be harbouring pests or diseases that you don't know about and when you put your new plants into it, they die. On the other hand, the compost may not be harbouring any pathogens at all - its a risk you either take or not. Certainly, if there's been any fungal problems with any plants in pots, the compost should be dumped and the container washed and sterilized before filling with new, fresh potting compost.

I should have mentioned that if you have any suspicion that you might have had vine weevils in your pots, definitely get rid of the old compost.

Thanks all I will investigate each pot with a beady eye!