Landscape timbers are a versatile and attractive way to add structure and visual interest to your landscaping. While not all landscape timbers are treated, those that are treated with chrome-plated copper arsenate (CCA) can be used in outdoor construction projects to resist rot and damage caused by the elements. However, prior to 2004, CCA treated timbers were infused with a chemical mixture of arsenic, chromium and copper, which is toxic to humans and other non-target organisms. If you use wood that may have been treated with CCA near an orchard, it is recommended that you cover the floor before installing the woods with plastic or other waterproof and non-toxic material.
Untreated woods that are naturally pest and weather resistant, such as cedar, juniper, and redwood, are ideal for use in gardens. Alternatively, you can research non-wood landscaping woods, which are usually made of plastics, metals, and wood composites that contain recycled wood fibers. When selecting garden timbers for your project, ask how they were treated so you can choose the right option before buying. Designing your treehouse with landscaped woods is a fun and rewarding project that the whole family can enjoy.
As the wood dries, it can split, bend, or warp, so it's not a good choice for making a patio bench. However, garden timbers are relatively inexpensive and easy to work with, making them an excellent choice for DIY enthusiasts. For the most durable ladder, use treated garden woods for the stringers (the supports that run perpendicular to the steps) and untreated wood for the steps (the surface of the step). Garden timbers are a great way to add structure and visual interest to your landscaping while also being safe for use in your garden.
Be sure to ask how they were treated before buying so you can choose the right option for your project.