Need for pebbles in air pot

No need to add anything on the bottom, just pack the bottom 2 inches down hard before filling the pots right up to the top. More soil = more plant. The soil will not wash out the holes if packed down firmly at the beginning. You want soil all the way to the bottom, otherwise once the roots get to the bottom, they will have no access to water or nutrients. The lower you can put the inner grid, the better. Air pots are great, examine the roots after harvest and you will be amazed! Hope this helps, Organoman.