dude ur fine, 30 sec, a min or even 2 min with a tiny flashlight is not gonna hurt, ive recently started watering at night due to paranoia that the neighbors see the same kid walkin up to the woods with a heavy backpack are gonna think sumthins up, i dnt wanna risk losing them i made it this far, ne way, ur plants are gonna need a substantial amount of light for a good amount of time, in order to "wake up " outta their sleep mode, consider the full moon on a clear night, if ur little flashlight would do nething to screw w/ the plants night/day cycle, so would a full moon, i am completely confident that even if u go up at night every day to check them for a min theyll still be fine,(not that ur going to) like i said ive started doing night watering, and i notice no ill effects in the least bit,the way light fucks up plants, is when indoor growers, check their plant frequently at night and turn their big ass hps on