Quote Originally Posted by keith_r
but they soon find that doesn't work..you need input!
I would argue that no natural system, anywhere on this Earth, requires human input to grow. I would further extend this premise to include properly designed AP systems as not needing human input (aside, perhaps, at initial construction). I have done it, the science backs it up, and it's actually a hell of a lot easier for a backyard gardener. Just food for thought...