I'm about to start my first grapevines and went out to get some cedar for posts -- I don't like to use pressure-treated because of the chemicals. BOY HOWDY is it expensive! My local lumberyard was asking $60 for a 4x4 by 8 foot post! I didn't buy them.

So what else can I use? I understand that I need 8 foot posts - 2 feet in the ground and 6 feet above. Can I use a metal U-post, like the kind they use in my part of the country (northeast) for snow fences? Or would that not be strong enough? Can I use a 4x4x8 Douglas fir, or would that rot?

Also, what kind of wire should I use? Need it be braided, or can something solid work?

I'm planting 2 vines, and the nursery where I am getting them says I need three posts, spaced 6 feet apart. The vines would be planted in between the posts:

POST grape POST grape POST.

Thanks!