>> >> one tall conduit pole in the middle to help support it,
>> use more poles (or boards) horizontally in between the posts,
Maybe three or even five light poles in-between the two sturdy ones.
Have you seen "Florida Weave"? If the upright poles are firmly planted, you can weave twine around the poles and plants to keep them upright.
http://www.youtube.com/watch?v...
especially from 2:50 to 5:30
Paracord is very stretchy. If you pull it tight enough to support much weight, the tension force on the cord might be 5 times the weight. It would be more suited to a veggie-flinging slingshot.
Better to add more upright poles. Rigid poles or boards across the top would allow all the weight to pull
straight down and be supported by upright poles that are stabilized by the weight, instead of relying on horizontal tension to provide upward lift.
Then you can hang netting from the top pole, or welded wire fencing, or hog panels, or "remesh" - a 6" grid of welded wire used in concrete like a checkerboard of very light-weight rebar. For veggies like peas that will cling to string, you can zig-zag twine between the top poles and some twine tied near ground level.
http://www.youtube.com/watch?v...
http://www.youtube.com/watch?v...
1:05 -2:05
If you have more than one row, a connected "grid" of poles or boards on top will stabilize the whole thing, one row supporting another, acting like the legs on a table, instead of having just one straight line of poles eager to fall over sideways.
