That's an excellent and very practical question! The short answer is: you *can* install a bench directly on soil or grass, but for stability, safety, and longevity, using a proper pad or prepared base is highly recommended. Let's break down why.
Installing a bench directly onto soft ground like soil or grass comes with significant drawbacks. The most immediate issue is instability. The legs will sink unevenly over time, causing the bench to wobble or tilt, which is both annoying and unsafe. On grass, the legs will kill the turf beneath them, leaving dead patches. Furthermore, constant contact with moisture from the ground will dramatically accelerate rot in wooden benches and corrosion in metal ones, shortening their lifespan.
For a permanent, stable installation, a prepared foundation is key. For most residential garden benches, the best practice is to use concrete pavers or patio stones as a simple "pad." First, excavate a shallow area slightly larger than the bench's footprint, level the ground, and add a layer of compacted gravel for drainage. Then, set the paver, check for level, and place your bench on top. This method prevents sinking, protects the bench from ground moisture, and keeps your lawn looking neat.
For heavier benches or in public spaces, more substantial concrete footings set below the frost line are often required. In casual garden settings, a generous layer of decorative gravel or crushed stone can also serve as a well-draining base that minimizes sinking.
In summary, while you can place a bench directly on the ground for a temporary look, taking the time to install it on a simple pad of pavers or gravel will ensure your bench remains level, secure, and beautiful for many more years to come. It's a small upfront effort for a major long-term payoff.