Most of these vertical gardens have irrigation tubes that continuously hydrate the plants. The system from Plants on Walls, which we used in our Creative Garden Retreat (http://bit.ly/gTSJQG), used these and the excess water is absorbed by the felt pockets, also helping to maintain even hydration. We planted ornamentals, but you can plant edibles–depends on your sunlight, etc. as always. Flora Grubb created stunning vertical gardens using Woolly Pockets and succulents.