I'd like to add supplemental lighting to my greenhouse. Currently I am using a string of contractor LED's at night just to trick the plants in order to keep them from flowering. Any idea how to figure out exactly what I need? My last grow averaged 4.8 oz per 30 plants, planted as clones and vegged for 30 days before turning the night lights off. This time I have vegged for 60 days, but due to the slightly shorter day (Hawaii) even with an extra month of veg time, they aren't that much larger than the previous grow. So this brings me to supplemental lighting to extend the "daylight" hours for growth (as opposed to just keeping the plants from flowering like I've been doing). I run 30 plants in 25 gallon grow bags in a 24X48X14 greenhouse. How do I determine wattage, spacing, hanging height, and number of lights? I can't seem to find an answer, believe me, I have read and read, so I'm hoping someone might be able to point me in the right direction. I figure since we get about 12 hours of daylight in the winter, and and the longest day is about 13.5 on June 21... the lights will be on long enough to provide lighting during the dark hours hours which will range somewhere between 6-8 hours per day.