Planter Liners for the Flower Boxes on Your Deck
Once you have finished decorating your deck with flower boxes, you will want to use planter liners to either protect the planters, to encourage healthy plant growth, or both. There are various types of planter liners available that are suitable for use in virtually every type of flower box, container or biodegradable coco planters.

Whether you have planted your own flower boxes or bought them ready-made, plastic planter liners or biodegradable coco planter liners will extend their life by preventing them from rotting. These planter liners are available preformed, or you can cut what you need from a large roll.
You can even use ordinary plastic saucer types as planter liners, but then you will need to allow for drainage, either by making holes in the planter liners. The best off-the-shelf planter liners include plastic or biodegradable coco planter liners, which provide some sort of drainage to prevent the plants from becoming waterlogged.
Innovative self-water, self-irrigating planter liners are a great time saver for busy people who either don’t have the time, or forget to water their plants, however can be quite costly. These plastic planter liners come in a variety of different shapes and sizes, usually with an insert that must be filled with water once every two or three weeks. These planter liners often take away the guesswork of how much water you need to give your plants because they monitor the moisture levels.

Suitable alternative types of planter liners are made from biodegradable coco fibers. Coco planter liners are readily available, and they absorb moisture nicely helping to keep the plants in a healthy environment. Coco planter liners are also inexpensive and add a natural appeal to outdoor décor.
Amazon Review November 30, 2013
Reviewer: Diane J Broadley
Just what I was looking for can't find them in the Winter in Georgia. They look great with my pansies in them.
Home Depot Review, Lasts a full year May 28, 2011
Reviewer: Chemar
I buy six new ones every year for my balcony planters. They look great and my plants thrive!
Home Depot Review March 27, 2012
Reviewer: Lizzy
The product is exactly as described, but the packaging could be better. Each liner is packaged in a plastic bag, which is great, but they are flat and folded. Considering the product is a liner I would not package them flat and fold them. Once you get them in the trough and add dirt they shape up pretty quickly.