@echloe - I use PVC pipe for all kinds of supports; first, I don't think you can get it in 1/4", but the 1/2" is easy to work with. It usually comes in 10-foot lengths; that would probably be a little long for a 3-foot-wide bed, I would go with something like 8-foot lengths, which would give you a support a little over 3 feet tall in the center. You can buy short lengths of "rebar" (used for concrete work) that can be pounded into the ground and the pipe slipped over them to anchor it down. Hope that helps - happy gardening!
