My wife and I wanted a simple line-trellis system that could be altered as needed, used for other types of vegetables, and could support shade material during peak summer months.

Each vertical is held with two single-hole straps, secured with bolts and nuts. (...not self-tapping screws as I originally considered.) I bought the 3d printed spacers, but they weren't needed.

I drove all four 3-4 inches into the ground, ensuring the top was level on all sides. The bed is on a slight slope, but I also leveled it. I'll probably add a central crossbar. If needed, I will also add 45-degree bracing, but so far it seems sturdy enough as is.

The nylon masonry line is tied on with double constrictor knots, and the lines are secured to the tomatoes with plastic trellis clips.