Results 1 to 12 of 12
Like Tree1Likes
  • 1 Post By Fuzzy Duck

Thread: How many lumens does a plant need each

  1. #1
    420 Member
    Join Date
    Feb 2012
    Posts
    95

    Question How many lumens does a plant need each

    i will be growing 3 feminized seeds from a new strain i ordered. Can anyone tell me if a 150w hps and how much cfl lumens i will need i have both 6000k and 2700k for each stage and have y adapters and a 4 way bulb adapters for the drop lights to have 4 bulbs or more on each plant with the hps above everything.
    so i heard 6000 lumens can anyone help? thanks

  2. #2

  3. #3
    420 Member Fuzzy Duck's Avatar
    Join Date
    Nov 2011
    Location
    The Compost Heap
    Posts
    2,586

    Re: how many lumens does a plant need each

    Not that lumens has any thing to do with plant growth as its a measurement of light visable to the human eye only !

    Its more about PAR, light spectrum & qualitie of it.



    But anyway in a nutshell…

    Lumens per square foot:

    Minimum amount of lighting needed is around 2000 lumens per square foot.
    (Two – 23 watt CFL’s, per square foot*)

    Mid range is around 5000 lumens per square foot.
    (Three - 23 watt CFL’s, per square foot*)

    Optimal is 7000-7500, or higher, lumens per square foot.
    (Five – 23 watt CFL’s, per square foot*)

    *I’m only using CFLs as a reference here, with the assumption they’re kept at a distance of 3 – 5 inches from the plant. It is important to understand that the “penetration” (the farthest measure that quality light reaches down into the plant canopy) will at best be only a few inches deep.

    Watts per square foot (wattage per sq ft WILL vary by light source):

    Minimum wattage per sq ft.: 30w
    Mid Range wattage per sq ft.: 50w
    Optimal Range wattage per sq ft.: 50-80w
    Jozo-sha likes this.
    We are a culture fully immersed in the ideology that truth is what we see and what we hear. Yet we hire lawyers to manipulate truth, we hire PR and marketing firms to create truth, and we hire investigators and private detectives to uncover truth. The problem to which I am affected every day is truth in the cannabis industry.

  4. #4
    420 Member
    Join Date
    Feb 2012
    Posts
    95

    Re: how many lumens does a plant need each

    would 24,000 lumens of light be sufficient for 3 sq feet? 150w hps and strong 6000k and 6500k cfls that hang close to the plants is what i am using right now

  5. #5
    420 Member Fuzzy Duck's Avatar
    Join Date
    Nov 2011
    Location
    The Compost Heap
    Posts
    2,586

    Re: how many lumens does a plant need each

    Quote Originally Posted by xave420 View Post
    would 24,000 lumens of light be sufficient for 3 sq feet? 150w hps and strong 6000k and 6500k cfls that hang close to the plants is what i am using right now
    Its more than enough.

    I would be inclined to switch the 6000k over to 2700k for the flowering phase tho
    We are a culture fully immersed in the ideology that truth is what we see and what we hear. Yet we hire lawyers to manipulate truth, we hire PR and marketing firms to create truth, and we hire investigators and private detectives to uncover truth. The problem to which I am affected every day is truth in the cannabis industry.

  6. #6
    420 Member
    Join Date
    Feb 2012
    Posts
    95

    Re: how many lumens does a plant need each

    yea i know cuz 2700k is as close a cfl gets to the 2100k hps produces. thanx

  7. #7
    New Member
    Join Date
    Jun 2012
    Posts
    9

    Re: how many lumens does a plant need each

    This chart is interesting:

    https://mycotopia.net/forums/attachm...hart.jpg?stc=1

    It's a list of lumens-strenght at different heights from bulb, for 250, 400 or 600 HPS.


    What I'm asking is: what does "optimal light" mean in this chart?
    Fat buds?
    A plant barely surviving?
    Popcorn buds?

    I ask because "optimal light" seem to have a very big range:
    At 21 inches, a 400W HPS gives only 5000 lm, and that is defined as "optimal light".
    At 22 inches, it's "too little light".

    This cannot be correct? I'm not sure how to interpret the chart, please help

  8. #8
    420 Member Smokemupm8's Avatar
    Join Date
    Jun 2012
    Location
    AUSSIE
    Posts
    3,066
    Blog Entries
    1

    Re: how many lumens does a plant need each

    i found charts giving the lumen output of both MH and HPS globes of various wattage, the closer to the plant the more lumens it recieves but you have to maintain decent distance to avoid burn but at like 5 inchs a 400w hps put out a 100,000 lumen so pending on size of ur plant the bottom canopy should recieve still like 25,000 lumens.. I have my light to move left/right/up/down so can get stronger light below too. Mayb GrowAddict means the same chart?? If you do a certain grow u can better dispense light over ur plant. Goodluk And Happy Harvesting

  9. #9
    New Member
    Join Date
    Jun 2012
    Posts
    9

    Re: how many lumens does a plant need each

    Quote Originally Posted by GrowAddict View Post
    This chart is interesting:

    https://mycotopia.net/forums/attachm...hart.jpg?stc=1

    It's a list of lumens-strenght at different heights from bulb, for 250, 400 or 600 HPS.


    What I'm asking is: what does "optimal light" mean in this chart?
    Fat buds?
    A plant barely surviving?
    Popcorn buds?

    I ask because "optimal light" seem to have a very big range:
    At 21 inches, a 400W HPS gives only 5000 lm, and that is defined as "optimal light".
    At 22 inches, it's "too little light".

    This cannot be correct? I'm not sure how to interpret the chart, please help
    bump.

    Take a look at that chart. Who decided that "optimal light" is 5000 lumen AND 63500 lm?
    Obvioulsy, "optimal light" is not big buds..... I wish that chart was better.

  10. #10
    420 Member Smokemupm8's Avatar
    Join Date
    Jun 2012
    Location
    AUSSIE
    Posts
    3,066
    Blog Entries
    1

    Re: How many lumens does a plant need each

    Hi Grow.. Yeah thats the one i have mate.. It is saying that the 'optimal distance' is the preferred range that the light will put out certain amounts of lumens for your plant. So in between say 3 inches above ur plant and the 22 inches ur plant will get at the top of the canopy '183,000 lumens for a 400w, while the lower branches, below the 19 inches will recieve less than 4,000 lumens, its basically saying that your plant at lower levels recieves less strength light, tho still able to grow ur plant, just slower than the tops closer to the light.. So you want to keep your lights close enuf without causing damage and i use a 400w and grew a 5 ft vert and the base levels matured abit slower but still was ready..That chart i found handy.. Its prob not 100% accurate but give you an idea anyway..You dont wanna put ur 250w say 22 inches above ur plant!!Or she will struggle.. I kept my lite at 8 inchs above tops. Goodluk and Happy Harvesting

  11. #11
    420 Member Smokemupm8's Avatar
    Join Date
    Jun 2012
    Location
    AUSSIE
    Posts
    3,066
    Blog Entries
    1

    Re: How many lumens does a plant need each

    OK Grow here's most my stats for ya... I kept my light always more than 6 inches from tops of my plant, to avoid burn, or bleaching or any stress its got a fan blowing directly underneath the light to help dissapate the heat. My plant reached 5ft tall at harvest time, ALL TOPS ( except maybe three small bottom levels like 4 inches above soil that were under alot of shade) grew well and each weighed between 8-14 grams when dried.. Some lower tops still made excellent bud, they still pulled at least 5 gram dry cola's and branches were full of bud.. So to answer the last 2 questions, only the first maybe 3 or 4 small levels werent as big as the rest, tho still a nice smoke-great high, and the only ones that were id say popcorn bud branches were stuff all but again, only due to shading factors i had trouble with on last setup.. otherwise id have to say a near perfect grow..Hope this can help you abit, just try to make sure ur branches are getting sum light on em and not always shaded,tuck or tie sum fan leaves if have to, and ur girl will grow ok.. Goodluk and Happy Harvesting

  12. #12
    New Member
    Join Date
    Jun 2012
    Posts
    9

    Re: How many lumens does a plant need each

    @Smokemupm8:
    Thanks for answering, but guess I should speak to the one who made the chart - as "OPTIMAL light" should give optimal sized buds - and it does NOT.

    I want optimal light-levels, but not only for my cola at the top.

    So I look at this chart, and it says "OPTIMAL LIGHT LEVEL" all the way from the very top down to only 4000 lumens... I call bullshit - that'll NOT give optimal sized buds.

    So how far down the lumen-table make for medium and popcorn-buds only?
    That is what I want to avoid, and I want to harvest it all at once - not top part of plant first to let bottom grow.

    You can help me (please):
    1. How many inches above the top of canopy is your 400W HPS?
    2. How many inches tall is your plant, from the very top down to pot-level?

    3. How many inches down your plant does your 400W HPS give you real good buds (at harvest)?

    4. At what height does buds only yield popcorn, if at all?

    Thanks, your experience with your 400W might help me a lot in my current situation.