I plant whenever the ground isn't frozen, though I tend to avoid July and August when it can be really hot and dry. Mine have done well planted in the fall and also have done well planted in the spring as soon as the ground was dry enough to work, the earlier the better so that they have a chance to settle in prior to summer's heat. After I plant I mulch to keep moisture more even.

I would plant them out this spring if they have filled the pots with roots, cut the vines back hard when you do so.

It is only tiny baby mail order plants that do a lot better for most in pots, and that is only necessary for a few months until they grow bigger.