Grapevine on a Deck We've recently moved into a house with a lovely south-facing 10' x 20' (exposed-aggregate) concrete deck. This deck is on the second level of a 3-storey house. It is soundly supported, and drains into the existing gutter system. We would like to make plans to build a pergola to cover most of this deck for shade, and to serve as the trelliswork for a vine of grapes. I would like to know the following: 1. Would CEDAR be the proper choice of building material for this pergola? Or would the more economical TREATED WOOD suffice? Would the TREATED WOOD leach harmful chemicals to the grape plant, and thus render the fruits not suitable for human consumption? 2. How much of a root system this size of a grapevine will need, so that I can build a properly sized and dimensioned (I'm concerned about the depth & breadth thereof), insulated, PLANTER BOX? 3. What type, or composition, of soil mixture is appropriate for this purpose?