I keep mine at approx 4 inches they are 4ft 4bulb T5 fixtures, stick your hand inbetween bulbs and top of plant too see how hot it is. all T5 fixtures produce different amounts of heat some more, some less heat, pointing a fan at the bulbs will help kool them, I would not put them at 1 inch away the plant could grow that in a day and get burned I suspect the 2 bulb units are kooler than 4 bulb,and it also depends on fixture design if there is ventilation in it or not, just keep checking heat level with hand between canopy under light, they work good for veg, you'll be happy you got them :hippy:
veggii Reviewed by veggii on . T5 distance? we got a 6 lamp, 54W each, 4' long T5 light system for the veg room. any input on what the distance from the tops should be? thanks, db:smokin: Rating: 5