newbie question about Hps

[Justin510]

I 400watt Hps is supposed to come today. and i was woundering how far above the plants it should be,
im going to try and flower some really small plants because i started sexing them and forgot to change the timer, and relized like two weeks later.

anyway how far should the light be above the plants,

i have about 4 feet to work with so would that make the light to close?

 

[kindprincess]

I 400watt Hps is supposed to come today. and i was woundering how far above the plants it should be,
im going to try and flower some really small plants because i started sexing them and forgot to change the timer, and relized like two weeks later.

anyway how far should the light be above the plants,

i have about 4 feet to work with so would that make the light to close?

start by hanging it three feet, run it for an hour and check temps, ambient and canopy. then lower it, about 4'' at a time, until you find your ideal height. it's always good to acclimate plants to hid's, starting with the light being higher than needed.

i keep my 400w about 12-24'' away from the plants, but mine are not aircooled. if they were, they'd be 12 inches all the time.

kp