I have done it to water some plants while on vacation, and I also grew African Violets that way, had them sitting on a grid over a tray with water, with wicks threaded into the pots from the bottom up.
I tested several types of potential wicks and found cotton shoelaces the most effective. You have to experiment a bit with how high to place the water container, since you just want to water your plant, not create a flood.
