Two options:
1. Hook up a sprinkler system with a timer (This is what I have done, but then again, I have 20 metres of shelves with over 100 trees on i)
2. Ask a friend to take care of them (I do this too, as a backup for the sprinkler, someone pops by every ther day to ensure all is running).
Misting is not needed, and does not help the way you might think. As for watering, putting it in a waterbad will compress the soild amking isvery wet and airless. IT is better to water from the top, when t needs water.