I just wrote an tutorial about self-watering indoor plants.
It is here: http://www.instructables.com/id/Self-regulating-watering-system
Hope someone find it useful.
How often do you have to refill the bottle or replace it? How big is the bottle? When plants mature, they can really suck up the water. Interesting experiment. Aloha
Well.... I'm testing it now (for 4 days) with two plants in small pots, and a 1.5 L bottle (one bottle for both plants). Until now, about 500 mL of water was sucked from the bottle.
I believe that a lot of water also evaporates from the soil (not to underestimate the plants thirst); so, if bottle size becomes a limit, maybe one can cover the pot with PVC film to reduce consumption... (Just an idea; never did it...)
Water is evaporating from the dishes as well. Approximately a 1/4" of depth a day in regular sunlight. Do an experiment with a cup of water and record the drop in water level each day. Aloha