Grape Trellis Questions
I am a newbie to grape planting and we need to put up a trellis. We planted 3 grapes in a line each 8' apart. At each grape we placed a metal fence post for the main "stalk" to climb. We have planned to put a 4"x4" post 4' on either side of each grape (total of 4 posts). The east end of the bed butts up to a concrete slab, so that corner post is unable to have any room outside the bed to make a good corner post (either a 2-post-with-angled-brace or a dead-man anchor). Here are some ideas I had that might allow it to work for my setup, so please comment on them if you think they will/will not work for my needs:
1) Use a "pipe" or some sort of solid "tube" as the top trellis line (possibly electrical conduit?). This would not pull like a wire would and thus I thought I could get away with no corner bracing. Can grapes grab something that big? What will work in the Iowa weather?
2) Use wire like a normal trellis, but use an inside angled brace (e.g. a 2"x4"). Something like this: http://images.scrippsweb.com/HGTV/2004/07/29/gby906_2l_e.jpg
Will something like that be strong enough? What should I use as the "base" of that angled piece? How far from the grape should I keep the bottom of that angled piece?
3) Concrete/gravel/etc the post hole for that corner post. Will that provide enough anchor to keep it from sagging too much?
4) Other ideas?
Remember that I should have support every 4 feet (the main posts and the fence posts at the plants). It is possible that in a couple years we may tear out that concrete pad anyway, but it is not in this year's plans.
Thanks for your help.