I like your innovative, experimental approach Geoff, as always. I have just added additional 40 Watt Florescent cool and warm T-8 and T-12 overhead lights. I have read a few places were in winter these lights should be on 14 to 16 hours a day. With your experience and expertise I thought you might comment as to what you think of keeping the lights on that long in my NORTHERN EXPOSURE greenhouse. Thanks in advance for your opinion! AL