Distance between the light and the plants
 

I bought 3 fluorescent bulbs which are quivalent to 180 watt, mounted on the ceiling and it is about 5 ft away from the plants. Is it okay or is the light too far away from the plants?

I do not have the answer but am considering artifical lighting along with natural light, so I am curious as well...

I'm pretty sure that's too far...I haven't tried growing under lights ever but the setups I've seen have the lights about 1-2 ft from the plants.

Depends on the type of bulbs. If you have the ordinary flourescents like you buy at Home Depot, etc. They aren't as bright as the ones intended for plants. With High Output (T5) type bulbs from orchid suppliers, you would probably have a bank of 4 ea 48" bulbs approx 2' from the plants. With ordinary florescents, probably 6" or so. Others here may have different experiences.

My 4 lamp 4 foot T5 fixtures are suspended 38 inches over the bench. The distance to the plant depends on height of plant. T12 fixtures should be mounted as close as possible to plants for the most part and for some orchids there will still not be enough light from T12s.

Ken

I have a 150W CFL about 18 inches above phal, paraphal, and phrag seedlings, and they show no signs of being overexposed.