I was coming back to fix my post since I realized I talked about keeping plants happy right when they're potted, and your problem is the ones you potted up awhile back. Once mine are stabilized they're good--but I've always been metered on water so I don't try to save water everywhere (unless I use a sprinkler, i am under the monthly amount included in the bill). The bins with a bit of water in them really do the trick for me, though.
Maybe there's a rain barrel in your future?
You have "pitimpinai's choice" going on with your dirt--lose your precious topsoil, or your precious purchased stuff!
