I hear that it's okay to have only green light on during the dark period, because the leaves don't absorb green light. Is this true? If I have to make an emergency visit to the room during the dark period, could I use a green light?
Yes it's true, still not good for the plants to see it too often because the green lights obvisously doesn't perfectly match all the green spectrum on the plant. So yes, you can use it for emergencies without negative affect.
