The first step is selecting the type of material you want to line your planter boxes with. As said, wooden planter boxes aren’t the only kind of planter you should use liners with; metal planters can also benefit from liners, although some come sealed already. However, steel planters, for example, can rust if they lack a protective coating. You should also use liners if your planter boxes are open on the bottom, as they work to keep burrowing pests and weeds out.
Plastic may be the best material to use as a liner, as it won’t break down with time. Many gardeners use pond liners for their planter boxes, as they’re sturdy and won’t deteriorate, protecting a planter’s construction thanks to the liner’s thick nature. Some professionals recommend using porous landscape fabric. These liners let water drain from the soil. However, the issue with these liners is that the planters will still come in contact with water — albeit, less than if there were no liner at all.
After you select a liner material for your gardening planter box, line the inside of the planter, covering all exposed surface areas. Next, temporarily secure it in place with clamps. After that, permanently secure the liner using a staple gun or drill. You’ll then have an outdoor wood or metal planter box ready for fruits, vegetables, flowers, and more.