This was way back in March, but shows the technique (if you can call it that) I use for making raised beds. The ones on the left were built last year, and the ones on the right were brand new. I concrete the corner posts into holes in the ground, then screw the sides – decking boards – to the posts. A good couple of coats of preservative and some plywood fillets down at ground level to cover any gaps, then they’re ready for filling. Hopefully they’ll last a few years.