So... When a plant does photosynthesis, part of that process is transpiration. Where the water in the plant leaves it in the form of vapor. As transpiration takes place, the roots absorb in water to replace what is leaving. This actually creates some pull, called transpiration pull. With a good absorbent soil base (sphagnum), with a good void ratio (via perlite and vermiculate for micro and macro pores), the transpiration pull can actually keep the soil at near optimum moisture by wicking/pulling from a reservoir. All hands free, no timers or valves, it just works naturally - waters itself just as much as it actually needs.
It's way common with much smaller planters. You see a lot of them made out of five gallon buckets or plastic totes that are stacked so the one on the bottom is the reservior.
I'm just trying to do the same thing on a larger scale. But... I'm afraid there is too much distance between the reservoirs and the soil, for one thing. And I'm just not sure about how it will work with a soil depth of about 18", for another.
But I figured it couldn't hurt to try.
I'm sort of guessing/hoping that it just "kinda" works. Which, in conjunction with my lawn sprinklers hitting it some every other day, might be enough to keep full size tomoato plants cranking along if I'm not there to water them for a week while I'm off running the Rubicon and hitting up Bodie and stuff.
Like I say, the concept is proven, but I didn't find any examples this size when I was looking, there is probably a reason for that... But, I couldn't help myself from trying.
- DAA