Composite lumber (Trex, recycled plastic)

Composite lumber, made from recycled wood fibers and plastic (brands include Trex, TimberTech, Nextwood), offers 25+ year lifespan with zero rot, no insect damage, and no painting or staining required. Up to 95% recycled content makes it an eco-friendly choice. The USDA organic farming program allows composite lumber for beds and fencing. The polypropylene binder does not leach toxic substances into soil. Composite boards are available in various colors for aesthetic flexibility. Key caveats: composite is significantly more expensive than wood (comparable to premium cedar or higher). It was designed for decking (horizontal, well-supported applications), so vertical use in raised beds requires additional structural support (corner posts, mid-span braces) to prevent bowing from soil pressure. Composite retains more heat than wood, potentially raising soil temperature. When cutting, wear a mask to avoid inhaling microplastic dust. Trex and Nextwood specifically state their products are suitable for raised bed and ground-contact use; verify with other brands before purchasing.