if u get the soil satureded before you leave and it's not to hott in your grow area your plants will have enough water to endure.. the only thing that sucks is say for example ur light falls, by 3 days your fucked.
Depending on the size of the pots/plants you can give them a generous watering and clip a 100 watt compact florescent over your grow. That will keep them in veg and keep the heat down while you're away. Don't forget to reduce air flow as that causes them to loose moisture as well.
