Lights, Lumens, Watts and Sq Ft Ratio

Discussion in 'Lighting' started by Dr_Green, Oct 6, 2010.

  1. #1 Dr_Green, Oct 6, 2010
    Last edited by a moderator: Oct 7, 2010
    I noticed nobody ever took the time and liberty to make a chart. With this chart you will be able to compare all aspects keeping in mind that the best ratio is offered by a 600w bulb!

    Having between 7 500 and 12 000 Lumens is good for growing with 10 000 lumens being optimal.

    Having 60 watts to 70 watts per square foot is perfect.

    Another advantage with a 600w there is a lot less heat. 40% less than a 1000w!

    This chart should be a Sticky...
     

    Attached Files:

  2. Lumens are irrelevant as they are a factor involved with the intensity that the HUMAN EYE perceives the light rather than how the plants can use it.
     
  3. Well a bunch of people ask about them so I put it in the chart as well as the watts ;) And also I went to horticulture school and they " the professional " told me that lumens to play a factor in the crops!
     
  4. True that lumens really isn't a measure of what we truly want to measure. But it still is some sort of measure of light output (the only one provided with most bulbs) and does serve as a proxy for what we want to know. Short of all of us going out and buying very expensive light meters, I am fine to talk in lumens even with the limitations.
     
  5. The chart is wrong though.

    Most 400 watt HPS bulbs produce 55,000 lumens.

    And MH produces 36,000 lumens
     
  6. Nope, 400w = 48 000 Lumens and 430w = 54 000 Lumens
    And this is only HPS lights no MH bulbs!
     
  7. Toasty is right ...............you can delve into PAR and more technical light measures But most bulbs are rated by lumens, charts are written in lumens, ect.
     
  8. I'm pretty sure you can read that I wrote 400w HPS and not 400w super HPS. If someone has a 400w super HPS they would just have to compare it with the 430w HPS. What do you think it that a logical idea?
     
  9. I was at are local green house and he showed me the difference in lighting that the t5 bulbs had about half the lumens of a 400w HPS. So basicly he told me that the less lumens the light has the closer you have to put it to the plant to be as effective. Just what i was told I use CFL personally and have the close to the little girls so the Lumens are not a factor for me.
     

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