Light Intensity Question

Discussion in 'First Time Marijuana Growers' started by HighBaked, Jan 2, 2014.

  1. Ok, so pretty simple question I am sure it is just being over thought. But here is the question.
     
    If I have a plant that fits within a 1.5x1x1 area and have it immersed in light from above and to the side, what is the lumens/ft<sup>2</sup>? I have mylar surrounding the plant and she is rotated daily so the plant receives equal light.
     
    Assuming that the bulbs are all 23w + 1600 lumens, would it theoretically be 6400 lumens/ft<sup>2</sup>  since I am only inhabiting the 1.5ft<sup>2 </sup>or is there some other answer?
     
     

     

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  2. With CFLs, I wouldn't really worry about what your lumen per foot is. Just always as a rule of thumb with CFLs; go buy more. Always buy more. If you're running them, get more than you have. 
     
    Otherwise, save up and buy HID lighting. 
     
    Also, side lighting as tempting as it may be, isn't really the best option. If you can fit the lights above the leaves, I'd say that's your best bet. If anything put them below the leaves. Since leaves will generally expose most their surface parallel to the ground, they won't expose much surface area to side lighting. 
     
    I've done vertical grows and the buds always grew one sided. It was really odd, but they looked odd.
     
  3. #3 HighBaked, Jan 3, 2014
    Last edited by a moderator: Jan 3, 2014
    The plant gets rotated every night so it receives good light all around
     
     
    I have a 150w HPS I used during flowering but the temperature started to get out of hand. I use a quieter fan because my goal is to keep it smaller and with an HPS and cfl's it was too much.
     
    What about the bottom layers of the plant. Shouldn't they be receiving light as well as the top canopy does? That is why I presumed that its would be good to keep some lights vertical.
     
     
    This is an aerial view.
    20131217_002543.jpg
     
  4. Technically, "lumens" is a way to rate the light output of the bulb, but it is not a measurement of the amount of light hitting an object at various distances. Especially with CFLs just follow the basic principles of more is better than less, and closer (until the point of burning) is better than far away.
     
  5. Yes, but the lumens/ft or lumens/m<sup>2</sup>, used in the inverse square law, measures the "lux" which is the intensity of light in that foot or meter squared. But anyways thanks all for the help. More CFL's is the way to go.
     
  6. ^Yes, all light (and other forms of electromagnetic radiation) follow the inverse square law. That's why I said closer is better than far away. You are wanting to calculate a precise lumens number based on dimensions and distances, I'm saying that's not how it works. The only real way to measure the amount/intensity of light hitting a certain spot is with a light meter, which won't measure lumens.
     
  7. So I just finished screwing back in the 150w HPS bulb. I also left 1 powerstrip worth of cfl's along the side. So my plant is now receiving 212w and a total of 15200 lumens. Think she will be fine?
     

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