I’ve been blessed with a big yard so growing vertically isn’t as pressing a need for me as it is for some of you folks who are growing on more limited plots. Getting things to go up, rather than sprawl, is particularly important if you have a tiny backyard.
Even though I’m not limited by space, there are some crops I grow that need to be trellised. Yard-long beans and West Indian gherkins will do terribly unless they can climb… and a lot of other vining crops are the same way.
If you really want a cheap trellis, you can cut and lash branches or bamboo together. I’ve done this and it works for a season or two. A better option are cattle or hog panels, which are basically a really thick gauge of galvanized fencing. They look a bit redneck compared to John’s set up, but they’ll last a lot longer.
A final option is to tack nails into a wooden fence and run strings in between them. I’ve done that with varying levels of success.