This is one of the crafty projects in Fern Richardson's book, “Small-Space Container Gardens: Transform Your Balcony, Porch or Patio with Fruits, Flowers, Foliage & Herbs” (Timber Press). The pebbles are for bees and birds to land on and drink.
Recycled Pallet Vertical Garden - Very little room on your urban porch or backyard? How about maximizing the space you have by growing up? I'll be using a pallet sitting in my back yard to plant garden center annuals or possibly native succulents.