I finally finished Muriel’s raised beds this past weekend. We talked about two different designs for these, one made of inter-lockable stacked cedar frames she could put together and vary the heights as she pleased, and this design.
The landscape tie based one is a variation of a planter she saw at one of the local garden centres. Each box is 4′ x 4′ and 30″ high. The height was based on my old garden beds in Saskatoon. “No Stoop Gardening”.
I didn’t use rebar as pins as is quite commonly done as the boxes are actually linked together and the measuring/drilling process would have been tedious at best and potentially frustrating with the slope of the yard. I chose to build them using 6″ spikes and a 3 lb hammer instead. Wow, did that ever give the elbow a workout.
My Elysium 
Those are TALL and look fantastic. I be they’d be easy to weed or pick the food from at that height though, nice job.