Great looking garden! I wish I had that much area to plant every year. Time for me to move to the old farm. I use rebar as well, and cut swim noodles into 1 1/2 - 2 inch pieces and but them on the top. I almost took out an eye a few years ago. Get the pink or red. I find them along the road during the summer.
Great tip! I have several noodles out in the shed. We cut the large diameter ones into foot-long pieces, tie fishing twine and a hook on them and use them instead of jugs. The bright yellow and lime green really show up, even off in the weeds.