You can absolutely protect a wooden park bench from termites without harsh chemicals by making it dry, elevated, and sealed. Start with the base: keep the legs off bare soil. Place them on concrete pavers, gravel, or metal footings so termites don’t have direct ground contact. Pull back grass, leaves, and mulch around the bench, and clear gaps between slats so moisture doesn’t stay trapped against the wood.
If you are choosing or replacing boards, pick naturally termite-resistant heartwood such as cedar, redwood, teak, white oak, or black locust. For an existing bench, fill cracks, joints, and end grain with exterior wood filler or paintable caulk, then apply a good exterior wood sealer, oil, or paint. Termites need moisture and hidden entry points, so keeping the surface sealed and dry is essential.
Physical barriers add another layer of protection. A fine stainless steel or copper mesh can be placed under the legs or inside metal brackets to block termite access. Food-grade diatomaceous earth can be worked into small cracks and joints; it dries out insects that crawl through it, but only while it stays dry. In the surrounding soil, beneficial nematodes are a natural predator of termites and other soil pests.
Check the bench every few months for mud tubes, tiny holes, or a hollow sound when you tap the wood. If you catch a small infestation early, you can spot-treat with an orange oil or neem oil solution, or use a borate wood treatment as a low-toxicity, mineral-based option. Sand rough areas and recoat the bench at least once a year. A dry, elevated, well-sealed bench with good airflow is the best long-term defense against termites without harsh chemicals.