Wood is a widely available and versatile material that can be used in many ways in the garden. Along with its natural color and texture, wood is also relatively to work with. Unfortunately, woods major disadvantage of course is rot. Fortunately, wood rot can be overcome and controlled.
Although the natural look of wood generally looks best, applying a finish can keep wood looking good for longer. Take precautions when choosing a finish so as to protect your fish. Microporous paints and stains all the wood to breathe. Applying sealant evenly is important because uneven seal jobs are at greater risk of cracking in time. Preservative free stains are available but keep in mind they are harder to find.
Don’t use preservatives on wood that comes in contact with your pond water. Be sure to treat the wood far away from the pond so as to avoid any possible chance of the preservatives getting into the water by accident. Always use low-toxic preservatives. Wood preservatives are often in a toxic-solvent base, generally including various pesticides and fungicides that can be lethal to fish and other pond life. Avoid solvent-based treatments when re-treating wood. Fumes from the solvent can even be lethal to fish. Timber is often pre-treated with preservatives so be sure to check before buying.
Promote rain water run-off by positioning wooden structures and edging in a way that won’t build up pools of water but will naturally run off. Although hardwoods are more expensive than softwoods, they are more resistant to rot than softwoods. Hardwoods are also harder to cut but are ideal for structures that will be supporting something, such as bridges that people will be walking across.
Softwoods can be sealed with clear polyurethane paints, or can be painted with low-toxicity bitumenastic paints. Larch is one of the most rot-resistant softwoods available. Imitation logs available from Japan are molded from concrete and placed around pond edges. After moss grows on them, they look rather natural.
It is very important to make sure that wooden slats in bridges and decking are secured safely before they are open to public use. Use rustproof screws when constructing because nails can come loose over time. Drill pilot holes first so as to minimize the risk of splitting. Load-bearing beams need to be bolted into position.