how far away from the bulb should the plant be?

[let_it_grow]

I'm going to a new setup for my chids and i wanted some advice on lighting. My plan was to put my high light plants under a 4 bulb ballast and my med light plants under a 2 bulb ballast using t5 lights. How far away should the plants be from the bulbs?

[neb]

How many watts are the lights? It also makes a big difference how far the plants are from the lights. A few inches can make a big difference.

[kenr62]

Probly as close as you can get them. with decent air movement, its doubtful you could burn them under fluorescent lighting. I have grown under 1000 watt HPS & MH within a few inches of the lights on moving tracks. To be safe maybe start a foot away and then gradually drop the lights until the leaves start to get a purple tinge...

[nhman]

Well........I would first want to know what type of orchids you are growing as that determines what light intensity they would "want".
Secondly, with T5's you can give Catts sunburns if left too close to the bulbs. Trust me - I've already done that experiment! Phals would just down right cook if too close.
As was suggested in another thread, a good light meter is your best friend. My Catts live, grown and bloom very well under T5's with my light meter reading about 1500 FC's.
Air movement, I've found, is vital as the T5's DO put out some heat. Not as hot as other types of lights, but enough to add to the burning effect if left too close without adequate air movement.