Help With Lumens?

Discussion in 'Growing Marijuana Indoors' started by tubbsy41, May 29, 2013.

  1. I'm a new grower and I was wondering if lumens are needed when vegging and flowering?
    Like do you need more lumens or less for either, all I know is one 23W CFL bulp produces around 1,500 lumens 
    could someone please just explain lumens in simple terms, would be a great help

  2. Bump

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  3. lumens per watt
    just tell you how affective the light is. 
    Its one of those thing you don't need to know.
    I have looked into it for years and it will never help me increase my yeilds
    The best way is to tell me the room size and I will help you work out the best setup for your room
  4. Also worth noting that lumens diminish greatly regarding distance from light, especially with CFL lamps where they are practically useless after 10".
  5. #5 hello ladies, May 29, 2013
    Last edited by a moderator: May 29, 2013
    you want as many lumens possible, most prefer anywhere from 5,000-10,000 lumens per square foot at the canopy level
  6. Cheers for all the feedback guys, I'm not planning on doing an inside grow for a good few months, was just curious to learn if changing lumens when vegging and flowering made any difference, is it just times then like 18/6 for vegging and 12/12 for flowering?

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  7. yes, cannabis bases it's life cycle around light timing, that's what makes it a "photoperiod" plant
  8. Thought so lad, cheers

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  9. lumens is a measure a candle light, not a scientist an not saying 1000 lumens is equal to 1000 candles, but it involves intensity distance from source n a few other things.
    lumens(lights) is nearly everything, the more u have the better yield, that is y we all buy lights to recreate what the sun does an has,(we cant come close) indoor plants 3-5 ft outdoor 6-9 ft easy all bcuz of light source an intensity, now enough of rambling.... what u want is 5000 lumens per sqft for good yields no matter wat size room, no less than half of that an optimal is 6500-7500 I run a 1000 hps n a 4x4x7 room that bulb by paper puts out 145000 lumens that puts me about 9000 lumens per sqft (not quite overkill yet) do a lil mo searchin a readin n itll start fallin together for ya
  10. lumens is a measurement of total light given off. contrary to popular belief lumens do not diminish with distance. lumen count stays the same but it is spread out over a larger area the further away you are. the intensity diminishes the further the light is away, but lumens is not a measurement of intensity. LUX is a measurement of intensity and this figure does drop considerably as you get further away from the light

    for a growing perspective I wouldn't worry about lumens, your best to compare using watts. even though watts are a measurement of electricity used, it is a universal term to describe how much light you are giving to your plants. for an example, if your using cfls then you need at least 60 watts per square foot of canopy. for hps you can get away with around half that, mh will be in between. but these are minimums. 100watts of CFLs per square foot is a better goal.

    another point worth mentioning is manufactures say all kinds of figures for their lamps when it comes to lumens. I don't believe a word of it
  11. You want atleast 5000-6000 lumins for veg and the bigger the plant the higher the lumins you want

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  12. #12 joe 60, May 30, 2013
    Last edited by a moderator: May 30, 2013
    I would agrea with that
    the thing is lums, lux, light spectrum, watts, type of light (cfl, t5,t4, mh, hps, led, at diffent  stages in growth from seeds to late flower can make every bulb diffent in how it effective the plant grows , how bushy, more crystals or how dank bud is in flower.
    you could right a thick book on it or talk about it for years
  13. I thought more towards the Kelvin scale 2700k for flower with it being red and 6400k for veg with it being blue and as long as you get that right and a high enough wattage you'll be fine timing on the light make a difference but I didn't think lumins make a huge deal but I could always be wrong
  14. ^^^ my quote button isn't working.....lumens is the measurement of total light, the more light the better (up to a point of course), so having enough light is very important. colour temperature is measured on the Kelvin scale, generally around 6400K is best for vegging and around 2700K is best for budding, but it's not a big concern, you can grow great bud using either one all the way through. people worry about the colour temperature way too muchwattage really has nothing to do with light, it's a measurement of power consumption, however wattage is a universal indication of how big and powerful the lights are as far as growers are concerned
  15. it won't let me edit that post, I hope people can understand my sloppy grammar and missing punctuation
  16. Thanks for clearing that up for me so lumin with bulbs do you add together the luminescence of 2 bulbs say bulb 1 is 1500L and bulb 2 is 1250L so total you have 2750L or is there a special maths that goes with it and what would you say would be best
  17. No lumens do not "add up" if you have two bulbs at 1500 lumens you do not have 3000 lumens at any one spot. You just have 1500 spread over a larger area. That is the reason cfl just can't compare to hid lighting.

    Light intensity does diminished with distance because it is spread, and effected by the law of inverse square. Even the intesity of the sun diminishes with distance, a cfl is certainly no exception to physics.

    Regardless of all the this lumens are a measure of how we percieve light and do a poor job of relating to plants. You can have all the light in the world and plants will only use a portion of the spectrum.
  18. that's it mate spot on, lumens is a measurement of total light, so you just add it up.

    you are wrong, lumens is not a measurement of intensity, just google it, it will take you like 3 seconds. a measurement of intensity is LUX, and that diminishes with distance. lumens does not diminish at all, it is merely a count of photons, this doesn't ever change with distence
  19. I will take your word for it. Not really worth the time to look it up when we are talking about 46w of cfl anyway.
  20. So many contradiction lol I will Google it myself so I know for sure thanks for advice

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