How far above plants to keep 400 true watts of CFL lighting?

Rum Nugginz

Rum Nugginz

Active Member
I am currently vegging in a 2'x2'x5' tent with 398 actual watts of 6500k cfl over the tops of 2 young plants (1 month old) early veg. I have (4) 65 watt and (6) 23 watt cfls arranged over the tops and the light is very bright. The light is arranged very uniformly and the lumens overlap each other making the light very intense. I do understand that in general, it has been said that cfl bulbs can be placed very close to the tops of plants when using single bulbs but when you start to incorporate a lot of bulbs into a small area, the lumens begin to add up and it becomes a whole different scenario. My question is, how far above the plants should 400 watts of cfl be hung? 8 inches? 10 inches? I currently have them at approx. 8 inches and there is what looks to be a bit of light bleaching starting to happen. I want to bring it up to a foot to allow the plants to be able to stretch a little bit as well. Just looking for some thoughts and opinions. Thanks
 
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Hson88

Member
I'm in a slightly smaller tent 3 x 2 x 3, iv got 200watt cfl on at 6400k starting them off and due to lack of space iv had the light at about 10" to a foot away I'm about two weeks in and have started to lst the two autos and seem to be happy, the other cfl is 2700k for when they start to show signs of flowering will move under that and start two more seeds off
 

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TomAce

TomAce

Active Member
spek9 said:
Most people do, but I would suspect that 400W worth of CFLs two inches away would burn the plant with heat.
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True, however, it's very unlikely he has 400 watts of CFL in a concentrated area...I have 270watts on my seedlings but as you see in the pic, it's spread out...during flowering, I have over 500 watts in my 4x4 all hanging 2-3 inches from canopy with no burns unless a leaf reaches out and touches one.
 
TomAce

TomAce

Active Member
TomAce said:
True, however, it's very unlikely he has 400 watts of CFL in a concentrated area...I have 270watts on my seedlings but as you see in the pic, it's spread out...during flowering, I have over 500 watts in my 4x4 all hanging 2-3 inches from canopy with no burns unless a leaf reaches out and touches one.
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First time grow (putting CFLs to the test)

Thought I'd share my first grow with the rollitup world! About my grow -Strains, 2 Sour Apple from seed and 1 mystery strain from seed(was really good smoke, that I can attest too:eyesmoke:..) -Medium is Kellogg's Organic mixed with perlite and worm castings. -Watering is strictly from bottom...
www.rollitup.org
 
Rum Nugginz

Rum Nugginz

Active Member
TomAce said:
True, however, it's very unlikely he has 400 watts of CFL in a concentrated area...I have 270watts on my seedlings but as you see in the pic, it's spread out...during flowering, I have over 500 watts in my 4x4 all hanging 2-3 inches from canopy with no burns unless a leaf reaches out and touches one.
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actually they are concentrated, I have (4) 65 watters, on Y splitters, (2) of them on one side, (2) of them on the other and in addition, I have (6) 23 watters on Y splitters (2) on each side and (2) in the middle of those in a 2x2 mylar tent, all of then hanging at exactly the same height same height directly over two 6 inch seedlings/early veg plants, it works out to about 100 watts per foot of actual wattage and approx. 6400 lumens per square foot as well, when the lumens start to overlap in a concentrated area cfl's do get very bright. I have the heat under control, it is the light intensity that is causing the stress.
 
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Rum Nugginz

Rum Nugginz

Active Member
TomAce, are those photography bulbs? They look familiar, I have used them in the past, the 6500k ones worked great!
 
Rum Nugginz

Rum Nugginz

Active Member
I have found a happy medium with the 2x2 setup, it is @ between 8" and 10" they are vegging the best right now. I am going to move them into a bigger tent with HID in a few more weeks.
 
Rum Nugginz

Rum Nugginz

Active Member
yeah, I saw them on Amazon but I decided to go right to the distributors website thinking I would get em faster. I got a decent deal, 36 bucks for 4 of the 65 watt ones but it may have been a bad decision as they are taking their sweet time sending em out.
 
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