A few years ago we used some prefabricated shipping crates as planter boxes. We spent considerable time and effort lining them, putting rocks in the bottom, and making them self watering. They worked great but now the wood is rotting and we want to keep the planter beds intact if possible. We are looking for expert opinion about the following; can we simply surround the existing rotting wood with new treated wood or other that will last much longer so that we can protect the shape and existing f lining and not have to start over? Or is this somehow a bad idea and we must remove all the rotting wood and refine things starting from scratch? We would love to hear from someone who knows planter boxes well about this.thank you!