according to my copy of Ed Frank's grow book, for light to affect the plant's cycle, it must be a light that is directly on the plant, and must light the entire plant ... a stray light catching a branch, etc. will have no affect (according to the book) ... personally, I leave my cabinet doors open when Im on the computer, sometimes for hours (its a couple feet away from me now) ... I enjoy the oxygen, and she likes my co2 ... never had a hermie, and my plants are typically without problems ... light, like temperature, and humidity, etc., all have ideal situations ... the plant will survive thru damned most anything, but to have healthy, productive plants, you want to try to stay near that ideal situation (but, no need to despair during minor fluctuations) ... :smokin: