Is it okay to leave your plants alone for a couple of days?

I'm going to start growing soon. Odds are that there's going to be a time where I'll be gone for a couple of days (2-3 at most).

So is that okay? I have a timer for the lights. Can I just put a cup of water in the grow box so it will evaporate and bring water to the plants?

search wic method

if it will only be for three of four days they should be fine, how often are you watering them now? the best thing (i think) would be to water them the day you leave and they should be fine till you get back