This isn't a plan, more a visualisation (drives OH bonkers) ;D ;D
Picture this, you have found 3 pallets that are all the same size.
Stand them up on their ends, say 2 or 3 feet apart - depends how long you want the bench to be.
Prior to this, you will have called into your local timber yard and purchased a length of ply or OSB, suitable to fit the dimensions of your pallet bases.
Put the sheet on top of the pallets and nail or screw into place.
Viola! a potting bench
Instead of the ply, you could also use the pallet planks to make the worktop - personally, I think life is too short to reclaim wood from pallets..........unless someone has a magic tip for separating the wood from the base without it splitting?