Multi-purpose will do fine but follow the advice of a fellow Goyer, sorry can't remember whom, and part fill your very large pot with compost; plant your 3 seed potatoes and cover to about 5cm; when the green leaves start to appear add more compost and keep doing so until the pot is full. Keep well watered and in a sunny position.

thanks for the advice moongrower

You are welcome Dab and have fun growing your potatoes!

I would stick to earlies and as well as plenty of water don't forget to feed heavily with potato fertiliser.

True Jimmy in pots they will need feeding

thanks once again moongrower and jimmytheone.but when do i use the potato fertilizer?

After the green sprouts (shaws)appear

thank you again moongrower