My husband and I were thinking of building this box and were right on the verge of heading to the store to buy the materials when a question arose. We're wondering if it's safe to grow food in this planter box - is it safe for the water to sit (for extended periods) in the perforated drainage pipe? Will the drainage pipe leach chemicals into the water? After all, these pipes are for *drainage* - water that's going away from houses and people, not carrying fresh water to them. I've seen claims that "Corrugated pipe is often made from high-density polyethylene or expanded polyethylene. It may also be made of polyvinyl chloride (PVC) or metal which are only recommended for drainage use when the water will not enter any drinking water system."

Are there any easy alternatives to a drainage pipe - something that's like a plumbing supply pipe, but flexible?