It’s the raw steel rebar you can buy at big box stores, just with a quick layer of paint. Epoxy coated sounds like a much better idea, but I have no idea where I would find that. They’re holding up really well, with just some spotty surface rust where I didn’t get great paint coverage initially. Rebar is very flexible at these lengths, so I tied the tops together and also tied the two rows together to prevent everything from flipping around so much.
And yeah, I often get overly ambitious with the quantity of things I grow, but going up helps in that regard. In addition to this bed, we have a large (8 foot tall, five foot wide) arch between two other beds that cukes, mellons, etc climb.
We had some volunteer pumpkins grow out of our compost pile and up the deer fence last year, so I’m going to intentionally use the fence for more growing area this season.