I am looking at using an existing building for a grow room but was a bit concerned with the ceiling height . It is a standard 8 foot ceiling , but the room is large enough to require HPS and MH lighting to be efficient I believe . My question is how far ( or close) to the ceiling can these lights safely be ? I have an option to use a building with 10 foot ceilings that would allow me to leave more ventilation space between the lights and to lid , but if my thinking is correct then I will have to run more lights because they will be higher up and diffuse more. Any input is appreciated.
Right up to the ceiling if they are in a cooled hood. I have a 5x5 tent. It is 78" tall so the plants get to a certain height and I tie wrap the light to the top of the tent. Right up against it. been doing it for 5 years. If the hood is cooled you are ok. Vertical bulbs I don't know.
I have 1000 watt lights very close to the ceiling in an 8' high room. My rooms are 12'x15' and I run four lights per room. I've set them up so I can raise or lower them but have found there is no need to lower them so I leave them at just below the ceiling. If u go with the ten foot ceiling you may want to lower them when the plants are small. All u need is hooks in the ceiling and small chains below them to hold the lights and reflectors