how high should my light be?.......some leaves feel dry.....i have lowered from about 0.5metre to 1.0metre........ do i need far more distance??????????????????they are 3weeks old from seed
With a 400w light, I think the norm is between 1.5-2 feet, though it can depend on the size of your grow area (heat). I would try starting at 2 feet and see how it does.
i started with my light about 3ft they were getting fried........i moved them onto the floor with the light now about 4.5 ft away and there about 21c and i repotted into 10L pots.....will they be ok
I don't think anyone can tell how far your lights should be without actually visiting your space. My suggestion would be use your hand with a little common sense. Four and half feet sounds like you have your lights to far to me. I would get you a fan like this http://www.walmart.com/catalog/product.do?product_id=9219112, its steel and runs like horse. I use them in a number of non grow applications as well. You can hang the fan level with the light to blow through it. I have done the same if you want to see it in my space. Honestly I grow right into the light with air cooled hood.
my 400MH are within 8 inches at times. the outside plants grow up into the reflectors...the key is to have a fan blowing directly on the bulb to keep the heat off the plant, and the room temps at 72* or less. its not the light that hurts them (once they are used to the intensity) its the heat. HPS radiates heat more than MH so they have to be further away... the MH doesnt have much radiant heat, so as long as u keep the air moving, it can be within a few inches without damage... wouldnt suggest it tho
thanks alot..........good pics what fan u using ruck or rvk?.........and can u use them cfl lights all the way through veg?
Not sure if I understand your question "ruck or rvk", the fan I was suggesting is in the link and is just used to blow across the hood of the light. This fan also worked well to blow through my CFL fixture you are referencing. When I had two spaces I used that CFL fixture for my entire VEG process. The plants you see outside of the room in the CFL Fixture thread are 38 days old. I had so much success with CFL's for VEG.