A neat trick to keep wood from soaking up ground moisture is to cut a couple of small pieces of old plastic cutting board and fasten them to the bottom of the legs. What also works is small pieces of wood with the grain running parallel to the ground. Those little pieces will eventually get ruined but the legs will be fine. I did this on some outdoor benches I made years ago, like 20 years ago. I have replaced the pads twice in that time but the bench legs are still in perfect condition.
"If you see a good fight, get in it." Dr. Vernon Jones