Page 1 of 2 12 LastLast
Results 1 to 15 of 25

Thread: What is the upper limit of lux/lumens/ square foot?

  1. #1
    New Member
    Join Date
    Jan 2008
    Posts
    0

    What is the upper limit of lux/lumens/ square foot?

    Hello everyone,

    "Assuming" a well controlled growing environment with near unlimited heat removal capabilities....what is the upper limit of lumens/lux per square foot?

    Assume a CO2 conventration of 1500ppm and a ambient temp of 80-82 F

    I understand that 1 1000W HPS is often used for a 4 x 4 area, has anyone tried 1500w or even 2000W per 4 x 4' area?

    Also, what are your opinions on using only a HPS bulb for veg and flowering? I've heard arguments that either MH or HPS are better.

    Thank you in advance for your responses.


  2. #2
    420 Member DankBuds's Avatar
    Join Date
    Aug 2007
    Location
    MidWest
    Posts
    121

    Re: What is the upper limit of lux/lumens/ square foot?

    I don't think there is one, lol The more light there better.

    DankBuds

  3. #3
    Cannabis Connoisseur Boss's Avatar
    Join Date
    Sep 2005
    Location
    Los Angeles, CA
    Posts
    7,976
    Blog Entries
    10

    Re: What is the upper limit of lux/lumens/ square foot?

    ^Correct. You can bleach them white with light, and as long as temps and nutes are correct, no harm done.

  4. #4
    New Member
    Join Date
    Jan 2008
    Posts
    0

    Re: What is the upper limit of lux/lumens/ square foot?

    Hi Guys,

    Thank you for the replies!

    I guess my question is, "Does anyone have any direct experience using more light that 1 1000 watt per 16 square feet?"

    It is my understanding the upper limit would be defined at the point where solarization starts to inhibit photosynthesis. I've read figures of 90,000 lumens per square foot as the upper limit with MJ.

    Also, what are people's opinions for veging with HPS bulbs?


    I am going to try a setup with 1500 watts of HPS over a 4x4 area and will post the results when I have them.


  5. #5
    420 Member Racefan's Avatar
    Join Date
    Sep 2006
    Location
    Northern California
    Posts
    3,549
    Blog Entries
    1

    Re: What is the upper limit of lux/lumens/ square foot?

    Quote Originally Posted by Boss View Post
    ^Correct. You can bleach them white with light, and as long as temps and nutes are correct, no harm done.
    Bleaching is a form of heat stress. The leaves slowly stop transpiration and slowly dry out from bleaching. This bleaching is detremental to bud growth as well for the same reasons. Smoking moose just posted a picture of one of urdedpal bud shots with a bleached bud top and you can clearly see the damage. Here's a link... What is the max wattage pre square foot?

  6. #6
    Cannabis Connoisseur Boss's Avatar
    Join Date
    Sep 2005
    Location
    Los Angeles, CA
    Posts
    7,976
    Blog Entries
    10

    Re: What is the upper limit of lux/lumens/ square foot?

    The damage on that photo looks more like bleaching and less like heat stress to me. That bud is full of crystals, and if heat had been the culprit, you wouldn't see many, and you would see burning. I really want to ask urded how that smoked, I bet it was good :-)

    Now if there had been more heat, I think it would have been a different story. He did that experiment very late in the budding cycle, so it was impossible to tell if it stunted growth. Although I can imagine if it stopped photosynthesis, it would.

    I am looking all over for the article i read on this subject... I'LL BE BOCK :-)

  7. #7
    New Member
    Join Date
    Jan 2008
    Posts
    0

    Re: What is the upper limit of lux/lumens/ square foot?

    Wow,

    This is all so new to me. The weed is so good these days, I remember the schwag we had back when I was in "high" school...late 80's was certainly not like this.

    I'm going to try a crop with 1500 watts of HPS over a 4 x 4 area and see what happens. Later, I'll conduct a more controlled experiment with the only variable being the wattage (same time of year/temps, etc) and see what happens.

    I'm not needing max output each crop, so I want to do my own research experiments just to see what happens.

    Fun, Fun, Fun

  8. #8
    420 Member Racefan's Avatar
    Join Date
    Sep 2006
    Location
    Northern California
    Posts
    3,549
    Blog Entries
    1

    Re: What is the upper limit of lux/lumens/ square foot?

    Hey boss...Urdedpal was just doing this experiment when I was brought on as a moderator for the site. This was approx a year and a half ago I believe. Him and I had a couple short conversations about it then. He even gave a smoke report I believe so that info might still be around. You might be able to find it by searching his posts.
    Newby...when I first started smoking weed we called a oz "lids". They were measure by holding your hand up next to the flattened bag and counted the amount of fingers it measured up to. IE...4 fingered lid or 5 fingered lid. The average cost was about $30.00. We didn't call it swag either. We called it commercial. lol They (the ounces or lids) were full of stems and seeds and harsh shit but you got stoned and that was the whole idea.lol It was nothing like what we smoke today although there was some good stuff around too. I smoked Hawaiian and Maui wowie and ohh....REAL THAI STICK! I miss the real Thai stick. That was the best IMO.

  9. #9
    420 Member alienpornopot's Avatar
    Join Date
    Jan 2008
    Location
    earth
    Posts
    144

    Re: What is the upper limit of lux/lumens/ square foot?

    hps is fine for vegging but 1500 watts are not recommended for horticultural applications.a 1000 watt is plenty for this space; any more ,from a single light source, is not only overkill but also produces mutated results (crystal free bleached out crap),hot spots and hard to controll heat. hang that sucker out in the yard where it belongs.

  10. #10
    420 Member alienpornopot's Avatar
    Join Date
    Jan 2008
    Location
    earth
    Posts
    144

    Re: What is the upper limit of lux/lumens/ square foot?

    if you want more lumens ... add extra bulbs of lesser wattage as opposed to the 1500 watt. i do know a couple of people who have used these bulbs and their results are never more than mediocre. eventually , they switched to bulbs with less lumens spaced closer. i personally follow the examples laid out in " how to supercharge your garden". these principles are designed to maximize production and potency in an indoor environment .a "must read " for all gardeners.

  11. #11
    420 Member alienpornopot's Avatar
    Join Date
    Jan 2008
    Location
    earth
    Posts
    144

    Re: What is the upper limit of lux/lumens/ square foot?

    if you are able to cool your space , hanging two 1000watts produces some dynamo results. if you crank the co2 and let the temp ride up to about 28degrees celcius your mind will be blown . remember...when your plants are running at this rate they will need extra feeding and you will want to closely monitor them for any deficiancies.

  12. #12
    420 Member alienpornopot's Avatar
    Join Date
    Jan 2008
    Location
    earth
    Posts
    144

    Re: What is the upper limit of lux/lumens/ square foot?

    i don't grow pot any more but , for flower crops , i use a twenty X forty greenhouse with a 1000wt bulb every three feet. some people would say this is overkill but my results are always healthy and top notch.

  13. #13
    420 Member Rocky Balboa's Avatar
    Join Date
    Jan 2007
    Location
    Canada
    Posts
    350

    Re: What is the upper limit of lux/lumens/ square foot?

    I am running 2x1000 watt lights right now. The bulbs are sunmaster 150,000 lumens. My table is only 3x4. My plants are looking great. This will be my best grow yet. Only 3rd grow ever. Then again both lights are vented out to avoid alot of heat problems. My temps at max is 29-30 celcius. Temps at lowest are 19-21. Humidity is always around 45%-50%.
    Im Legal To Smoke & Grow!

  14. #14
    420 Member Rocky Balboa's Avatar
    Join Date
    Jan 2007
    Location
    Canada
    Posts
    350

    Re: What is the upper limit of lux/lumens/ square foot?

    My grow is 8x6x6. I am not running co2 from the tank yet. I still have to buy that. How much of a difference would that make?
    Im Legal To Smoke & Grow!

  15. #15
    420 Member alienpornopot's Avatar
    Join Date
    Jan 2008
    Location
    earth
    Posts
    144

    Re: What is the upper limit of lux/lumens/ square foot?

    bringing your night time temp up to around thirty will greatly benefit your plants . they will be much more compact with less temp variation . remember too, that after thirty degrees, photosynthesis becomes impeded by the heat causing a total stall in growth and flower potential. always keep day time temps below thirty. if you are adding co2 , it is good to run a warm room. big open stomas operating at max capacity. you must remember that the plant is going to want to be fed more often when it's system is running this fast . the tech is called supercharging . greenhouse and indoor peeps use it all the time to grow all the quick growing C3 plants. this is how they do things like growing shitloads of bazil on a few 4X8 tables. this combined with some strategic pruning can make for some bumper harvs off of relatively minimal spaces.
    grow food

Page 1 of 2 12 LastLast