the box that i am planning to build may be a little small height wise. i was wondering if a pot could be say 5 inches high, but 12 inches wide, and still be as effective as one that was deeper, yet has a smaller width (traditional pot). thanks!
not really. the taller the bucket, the better the drainage. Put a sponge into some water and get it full. Take it out horizontally (flat) and just hold it until the water drips completely out (dont' squeeze). Now turn it up on the shortest end so it's up and down and look at how much more water comes out. Same with plant pots.