I'm just going to throw this out there. It is old school shit that a friend of mine used when they went away for 4 weeks and could not water.

They set up a wicking system with sterilized shoelaces and a 5 gallon bucket of water. They poked a whole in the medium, dropped one end of the shoelace in about 6"'s and gently packed the medium around it. Took the other end and dropped it into the bucket and taped it along the edge to insure against it dropping out. They did this with 6 plants but I'm sure if you rig it up right it could water more in the amount of time that you will be gone.
:rastabanna: