I would worry the outer pots would hold too much water. You might try a trick I use. I double pot a lot of things, especially ferns which take a lot of moisture but don't like wet feet. As long as the outer pot or cloche pot is outside you can have and should have small holes in the bottom or around the bottom edge. To retain and maintain moisture, place a block or two of Oasis foam in the bottom of the outer pot and set the inner pot on top of it. Then fill the rest of the cloche pot with Perlite. Don't use tap water unless you have a well but water the Perlite to maintain high humidity around your mini bog. If you must use tap water allow it to sit overnight to reduce chemicals. The Perlite will filter out most of the rest. The Oasis should keep enough water available to keep the pot happy with less attention. I don't know if the dirt and stones will do the job. I do know that without drainage it will become stagnant and you bog plants will rot. You might want to add part of a mosquito dunk. The inner pot should be terracota or other porous material. Sandy