Lightning

[hc5guam]

I have a 400w that i will be installing. I am 21 days into my grow from seed. Running 18/6 during veg. How high off the plants should the light be?

 

[420fied]

It depends on your grow space and ventilation. What is the temperature of your grow room with the lights on? Are you using an air cooled hood or a regular reflector?

If you have good ventilation and air movement you should be able to keep the 400 within 12-14 inches of the top of your plants. With good air movement and an AC, I'm able to run 600's with regular quad reflectors and keep them 14-16 inches from the tops of my plants.

Best of luck.

 

[hc5guam]

I appreciate the advise. I currently have it at about 24". I will lower it a cpl inches everyday till i find a comfort zone.

 

[420fied]

Good idea. The general rule of thumb is that if the back of your hand is uncomfortably hot when held at the tops of your plants..... the light is too close. If your hand is comfy, then your plants will be comfy as well. Best wishes.

 

[Twelve12]

I usually keep it at 2 feet away from the top cola. That's with 600w MH. Temp is around 75-80F. If you are using CFL light you can have it closer.