Can Composite Decking Be Used for a Garden?

by Renee Miller

Composite decking is a manufactured landscape product made to look like real wood. As a replacement for wood in your garden, composite decking is an option that won’t leach toxins or environmental contaminants into the soil, and it requires almost no maintenance. However, some factors may make it unappealing to gardeners.

1. Inside Composite Lumber

Composite decking and landscaping timbers are typically made from wood fibers that are combined with recycled plastics, such as high-density polyethylene plastic, low-density polyethylene, polypropylene and polyvinyl chloride. Composite lumber may also be made from natural fibers other than wood, such as rice hulls, straw and flax. The combination of natural fibers and plastic creates a product that is long lasting, resistant to pests, moisture and fungi, and requires no sealing.

2. In the Garden

Composite decking can be used in your garden, and because it's often made using recycled plastics and wood by-products, it's an environmentally friendly alternative to wood. In your garden, composite decking can be used as an edging material, and with some limitations, to build retaining walls. Composite lumber can also be used to build garden benches, raised walkways and planters.

3. The Pros

Composite lumber resembles real wood and has a long life compared to materials such as wood and stone, which are vulnerable to moisture, cold and heat. Composite products resist moisture penetration and won’t crack due to temperature fluctuations. They also resist fading and don’t require painting or sealing and are extremely low maintenance.

4. The Cons

Composite decking is designed to resemble real wood, but it is obvious that it is not. If you like the appearance of natural materials in your landscape, you may not find its appearance appealing. Composite decking is also expensive and can cost three to four times as much as standard treated pine decking. While it resists fading, the color will lighten over time. If it is damaged, composite decking must be replaced. The durability and life of composite decking when it is placed in direct contact with the soil as a garden edge is uncertain, because these factors have not been thoroughly tested. According to the University of Georgia, studies on composite material used for decking shows that it experiences some of the same forms of deterioration as wood products, such as mold, discoloration and degradation.