the reason i liked to use twine...and that i think 100% cotton yarn is a good choice...is that they biodegrade. when it comes time to put the garden to rest for the winter, i want as little work as possible. i just rip out the vines, clipping string as needed to be able to remove the cages, and plop the whole vine mess into the compost. it all turns back into rich soil over time... vine, twine, yarn and all.
love,
jane