I just changed my light from a 125 watt cfl to a 400 watt hps. Since im not formilar with type of lighting i have a few questions. How close do my plants need to be to the light or how far should i keep them from the light or is it just depending on temp of the plant tops? I have them in a 2.5 foot by 5 foot closet space. Also the ballast what type of surface should this be keeped on? I have it on a piece of glass is that ok?
Can any one answer my question?
- Thread starter reuben85
- Start date
J.cun.Shallow
Active Member
you want the light as close as possible without it getting to hot for your canopy, but becuase you just introduced your plants to this light I think you should have it a higher to start with so that you dont shock them
12-18 inches from the top of the plant. if it is a clone or young seedling 2-3 feet to start and move the light a few inches closer every few days. This is how far I been keeping my 400 watt HPS light from my plant tops, and Its been working great for me. Also, I have my ballast screwed to my ceiling, but your peace of glass should work just fine. Keep a fan on it if you can, a cooler ballast is a happier one!
Silky Shagsalot
Well-Known Member
once beyond seedling stage, use the back of the hand test to check for distance. (fan blowing on ballast works very well!)
proheto8008
Well-Known Member
Once they have grown up and gotten used to the HID you can keep em 12-20 inches away. 20 inches is on the far side for a 400 watter. Keep em closer to 12 inches.