I'm building a trellis to grow my tomatoes on this year, and I used two long maple poles sunk in the ground, connected with very stiff and heavy wire. I've inserted one tall conduit pole in the middle to help support it, and the wire has a turnbuckle on it to tighten it, but it's still not as taught as I'd like it to be. I was thinking about replacing the wire with heavy paracord, since it's so strong, but I was worried because I can't find anyone else talking about doing this online. Is there something I'm not thinking of? Would it be too stretchy? It's supposed to be UV resistant, but I'm wondering how long it would really hold up in comparison to the wire. It's obviously MUCH easier to work with, and I think I could get it a lot tighter with the right knots. What do you guys think? If it works, I'll be sure to post in the Ideas section :).

I don't think your trellis will ever stay tight unless the poles are sunk into cement, or otherwise supported; for instance, I have a long (30') bean trellis that is supported by big metal "U-posts", which are pounded into the ground and also bolted to railroad ties that border the garden. And we had a similar problem with the sagging with our "grape arbor" (we have 6 grape plants, just started a couple of years ago, supported on wires stretched between 4x4 posts). There are 2 rows, with a post at each end 20' apart, with 3 wires strung in between (also with turnbuckles). After this past winter they were sagging dreadfully, and my husband has recently dug down around each pole and poured in a good amount of cement for support -- hopefully that will solve our problem; there certainly will be he** to pay if we ever have to remove those posts!!

What might work for your tomato trellis is to use more poles (or boards) horizontally in between the posts, so that the trellis is more rigid. Hope this helps!

with Sandy.

Here's a great idea that I'm planning on trying this year http://garden.org/ideas/view/R... . This, to me at least, looks about as stable as you can get without using cement.

>> >> 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.

I think using the hog/cattle panels, or remesh (concrete reinforcing welded wire), is a really good suggestion. I've wanted to get some cattle panels to use for vertical growing, but I tend to get paranoid about hauling stuff and can picture having the panels in the back of a pickup truck as per Ravencroft's description, hitting a bump and having them spring out and kill some poor passerby...

I did buy a 50-ft roll of remesh this year and have used part of it to arch over a steel hoop house frame to grow some gourds, cukes, etc. on this year. That roll is more than a little unruly, though, so I was pretty happy to survive that little project without needing any band-aids (or worse). Remesh can be bought in panels, however, I think 4x8', which would be much more manageable and easy to transport. The biggest drawback is that it does rust, so expect to be kind of a mess after dealing with it! At any rate, cattle panels and remesh are nearly self-supporting and really eliminate a lot of hassle with the framework.

Weedwhacker said: I've wanted to get some cattle panels to use for vertical growing, but I tend to get paranoid about hauling stuff and can picture having the panels in the back of a pickup truck as per Ravencroft's description, hitting a bump and having them spring out and kill some poor passerby...

Me, too. That's why I never tried it before, but the suggestion of arching it between the sides of the truck bed instead of having eight feet hanging out and flopping around beyond the tailgate sounds good. A couple of bungees or a tie-down across the top should hold it steady.
We live on an excessively bumpy road that also carries some pretty deep swales...I'll strap mine down for sure.