Amber Beckerson

I wonder if you'd get more water collection if you used metal condensers inside of the rock pile. They would certainly be colder than the rocks surrounding them. Copper or stainless steel would probably be the best choices for the cleanest water, but if you're just watering plants, steel pipes would probably work well enough.

This must be where Frank Herbert got the idea for "wind tunnel moisture traps" used by the Fremen in the "Dune" books. I always wondered how possible it was for that to actually work.