We are looking to replace the hardie fence with a new colourbond which will be built with 2 x plinths (150mm each and 1.8 m panels, giving us a total finished height of 1.9 - 2.0 m. The new fence is yet to be built. Once the color bond fence is up, we are looking to build a garden bed using H4 sleepers as per video - Build a garden bed with seat (youtube.com).
Since the garden bed in the front will be 450mm high, what's the best material we can use that can be attached to the fence or installed on the ground to stop the soil touching the fence and slowly damaging it. Another plinth or is there a more suitable option.
Existing Fence
Garden Bed Design