plants do NOT have a set time when to drink. they are thirsty when they are thirsty . I think they keep sucking the water all the time and once a spot gets dry it sucks it up . or keeps sucking so it never has a chance to get dry. no plants don't really suck like on a straw don't pick on me to much lol . I suggest to water in there morning so they can use the water right away and if any water is spilled it has a chance to dry up from the sun your supplying . it does not matter . what ever is best for you is the best choice . also I have seen plants herm from the green light that they are not expose to see . mabe it was a cheap bulb idk it was green so water during there day only . my opinion . and from experience