What is your average rainfall in the area at this time of year?
Let's just cut to the chase here. More than likely you can get away with a weekly watering in the beginning. As the plants grow, they will start to need more. I'm guessing you will have no idea if it has rained on your plants, so I think you are going to make quite a few trips up there. Next time you are there stick a cheap rain gauge nearby, that should help guide you.