I don't think you can stop it, you can slow the rot by sealing the wood, or using pressure treated wood.
Better yet, use vinyl (or PVC) boards. The PVC boards are available in various sizes, which can be cut it to the size you want, so you can make your cross. It can be painted it you don't want it to be white.(If you buy the board at Home Depot, or Lowes, they'll make the cuts for you.)
Some of these boards even have a simulated wood grain, so it even looks like wood.
Use 40 year pressure treated wood which is specially made to withstand long periods in soil.
What is the best way of keeping wood from rotting if you're going to put it in the ground ie ( cross at cemetery )? 2" x 3"..Thanks in advance Ed
