When building our raised garden beds five years ago, we decided on untreated wood planks for the sides to avoid the chemicals found in treated wood. They work just as well as treated wood. In late April as we began preparing the garden beds for the spring planting, I noticed the insides of the 8X4 planks were beginning to deteriorate. This is natural as they have sat in water and soil for so long. And given they’ve worked so hard for our gardens, I wanted to extend their usage.
I decided to line them with industrial-grade garbage bags, stapling them all around, but letting the bottom stay open for drainage. A Pond liner can also work but can be more expensive. This treatment will keep the planks going for a few more years. And given the cost of wood these days, that’s a really good thing! The black lining will also absorb heat so that the soil will be warmer, helping the vegetables grow when I plant them in my newly transformed raised beds.