Hi There….. If using the AirDomes…… Place AirDome in each pot and cover with pH stable pebbles or a very open substrate…. cover with pebbles so you can just see the top of the AirDome. Also the substrate of choice is also important and must also be open and air retentive….. Please take a look at the potting up guides and brochure on the home page as this may well help answer some additional questions you may have.