tubers? and how to combat ants?

Hi everyone I have a bunch of dahlias.zantedeschias and polianthes tubers is it ok to put them straight out in the garden now? Or best to pot them up first but don't really have space to grow them on in our conservatory as full of other plants, also any ideas how to combat ants? I've noticed quite alot in our front garden and I'm worried they start eating all our plants is there a type of plant that can deter them? Or any other options. Thank you. Sam