The short answer is to spread the load and create a firm, drained base — don’t just put legs straight onto soft grass or loose gravel. I’d start by checking what’s underneath. If the ground stays wet or spongy, no fancy foot pad will fix it for long. Remove loose gravel or dead grass, compact the soil, and add a layer of crushed stone or a paver base. For a single bench or table, a simple patio slab under each leg can be enough. For heavier or rented furniture, use a wider platform: interlocking deck tiles, a small wooden plinth, or a concrete paver. The goal is to get the weight to spread over a larger area, not four tiny points.
On gravel, I like a gravel stabilizer grid or honeycomb mat filled with fines, especially in walkable urban spots. It keeps stones from rolling away and stops legs from burrowing. If you can’t dig, put down rubber or composite load-spreading pads, then a paver on top. Avoid thin plastic feet — they crack and sink. Look for furniture with wide, flat feet, and add furniture cups or shoe-style glides with a broad base. For benches and planters, bolt or strap them to a stable platform if wind is an issue, but don’t anchor into loose gravel alone.
Drainage matters too. Clear grass clippings, avoid overwatering, and keep runoff from pooling around legs. In shared urban spaces, check rules before fixing anything permanent and use removable bases if needed. A quick test: press down on one leg. If it moves more than a little, add more base area. Cheap fix first: pavers plus rubber pads. Better fix: compacted sub-base plus stabilizer grid. Best fix: a small paved pad or deck platform. That’s usually how I’d stop outdoor furniture from sinking without turning a lawn or gravel bed into a muddy mess.