Devon,
United Kingdom 
I have some decking, 3-4 feet from the ground. For the last 3 years, I have grown grape vines between the posts that hold up the decking, and above the decking along wires under the fence.
I have now added some posts that go 7' up from the decking, and added some horizontal beams that go from the posts to the house. I intend to thread wires through the beams to persuade the vines to grow like a roof over the decking.
How should I prune the vines so that they spread over the beams above the decking? Cut all branches away except the main ones, and tie them to the posts? Or just intertwine all the branches up the posts?
Thanks for an advice.
John
23 Dec, 2009
Answers
Yes, Join Goy and send us some pictures so that we can see what you are planning.
23 Dec, 2009
I have seen it done here, and you keep the main vine trimmed, allowing it to reach the top (unless you want it to spread and create a wall and then you would need horizontal wires to train it on), and then prune back to major joints each year. Grapes grow quite a bit each year, so a lot of pruning is involved. But they do look nice in July and August.
24 Dec, 2009
Previous question
Hi John
You really need to join GoY so we can have an interactive talk. Right now we can give you suggestions but we can't ask questions (well we can lol) as you can't reply. What you are doing sounds like an interesting project come on in we don't bite...
23 Dec, 2009