I think mine are under 18-24" of water in that pond now. Between the circular water flow I've set up and the all of the fish movement I figure the gases move around all right. I weigh the tops of the pots down with large rocks, but otherwise plant them all similar to what I described above, with leaner or richer soil sometimes depending on the plant. I always put them in nursery tanks for a couple weeks after potting, though, to let them root in well and elongate their leaves to the level of water in the target pond. Small poly stock tanks are good for this.
