If you're looking for a material to line your wooden planter that will provide both drainage and support for your plants, coco coir is an excellent option. Coco coir is made from the husks of coconuts, and it has many benefits as a gardening material. It's environmentally friendly, since it's a renewable resource, and it's also biodegradable. Additionally, coco coir retains moisture well, so you won't have to water your plants as often. It's also incredibly sturdy, so it can support heavier plants without breaking down.