Great info. I'm just amassing the bits & pieces needed to start growing and was wondering about how to combat heat in summer (in my case australia, and it gets hot! and will do in my intended grow area, esp as summer will be well on the way by December) So the lights off at the hottest times makes great sense ;)
That said, I do 24 hours with it's really cool parts of the year, and can use the extra heating in the house, and warmth for the plants. I agree 18/6 has it's advantages. Would be cool to see one on this regarding flowering, and techniques to speed the ripening process along in some situations.
I keep mine on 24. What I use are the low watt (13) / 100 watt output "green energy" bulbs. Keeps my meter from spinning like a Frisbee on meth. Three bulbs seems to be more than enough light in a 10X10 room. Bonus is the bulbs have a 10 year life according to the package and guaranteed.
This is answer my question, I have my one seed under 18 hours light since 25th January, it is just coming to the 3rd set of leave,roots appearing through bottom of pot.I think to transplant to a bigger pot in a week , I want to delay flowering till its hopefully a dwarf conifer size and bushy, then take outside gradually increasing the natural sunlight hours knowing that it starts to flower, as I read on countless forums. This is my first time with lights using a 50watt Led.