Raised garden beds have a lot of things going for them, including better soil, less soil compaction and simplified maintenance. You can make them in just about any durable material, but timber is a common choice because of its natural beauty and durability. Any kind of wood will eventually decay, but some kinds are more durable than others. Choose a rot-resistant variety, and intend to replace it every 10 to 20 years, depending on your climate.
Kind of Wood
Untreated timber, like pine, is actually the least durable and is not suggested. It will warp and begin to decay within three to five years. Cedar and redwood are naturally resistant to both decay and insect infestations, which explains why they’re frequently used for fences and decks. These substances will generally last 10 to 20 years in a raised-bed garden. Wood composite products, produced from a combination of wood fibers and polypropylene with ultraviolet light protection, tend to be used as decking materials because they are quite durable. Concerning splitting, discoloration, mold and mildew, they seem to be about as durable as cedar, as stated by the University of Georgia Cooperative Extension. Pressure-treated timber is also very durable, but it is not recommended for vegetable gardens due to the probability of damaging chemicals leaching into the ground.
General Conditions
Another factor to consider when choosing wood for a raised bed is the climate. In dry climates, cedar raised beds last a long time. In wet climates, the timber rarely has a chance to dry out entirely, which can drastically lower its durability. How frequently you irrigate the garden also makes a difference. Wood in vegetable gardens that require a lot of water will decay faster than people in a raised xeriscape garden.
Aesthetics Count
Durability is not the only thing to think about when choosing materials for a raised garden. Think about the type of your garden as well as your aesthetic tastes. A lot of folks prefer the pure elegance of raised cedar beds. Cedar fades in a warm brown to silver as time passes.
Other Options
Wood is not the only material available for raised beds. Look at making raised beds from rocks or cinder blocks, especially if you expect to keep the bed for several years or you live in a wet climate. Many commercial gardens utilize recycled plastic for raised beds. Aircraft plastic comes in many colors and will last indefinitely. However, it’s possibly the most expensive material, though you may spend less in the long term due to its durability.