Question
We'd like to build 2-3 plants beds on our enormous wood deck.  Our backyard is well shaded by trees and in order to obtain max growth on our plants and herbs, we have to plant on the deck itself (in pots last year).  How should we go about this?  That is, I can build it, but what do we put underneath?  Will building on wood affect the deck itself (i.e., rot)?  Or, can a cover of some sort help alleviate this (like gravel or charcoal used in aquariums)?  Thanks.

Answer
Hey, Lew.

Based on my own past experience loading my wood decks with all sorts of pots and planters, here's what I would suggest you do.

Build your planters so that when they are full of soil, you can still move them. In fact, I would put rollers on them. They make outdoor rollers that allow you to roll them here, there, and everywhere. That in and of itself will raise them off the wood deck by a couple of inches which will allow any water draining from the planter to evaporate rather than being held underneat the planter and rotting both your deck and the planter. Move them a couple of inches back and forth once a month so that the small section under the rollers doesn't rot out.

Hope that helps.