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  • #16
    Measuring Lumens or luxe is really the only way to accurately measure how much light is reaching your plants. For various reasons- space, electricity draw, etc. I chose to try LEDs.
    Measuring watts with LED's is not really a good way to measure light output, really it only a measure of the amount of electricity required to run your lights. After my previous post about LED's I decided to use a light meter to measure the light at the tops of the plants and midway down (a distance of about 12-15" average for 6 plants. The intensity of the light measured 12" from the tops varied (anywhere from 50-90% of the light measured at the top), but at the tops it was consistent. I used an old light meter (photographic) to take these measurements (it measures lumens) and it seemed to be pretty accurate.

    For those of you who have a "geeky" side here's some more info_
    An article I ran across published by some researchers who were comparing how much light is produced by various types of lighting and how that light was actually perceived by the human eye provided the following information (I'm not going to include the comparisons between lumen output and human perception because its not really relevant to plants)_ so here's what they found_
    LED's produce about 100 lumens/watt
    HID/MH produce about 90 lumens per watt
    HPS produce about 110 lumens per watt
    LPS produce about 130 lumens per watt.

    These measurements are in lumens (which measures direct light output and is what my light meter measures).
    However meters that measure perceived light at different distances and coverage patterns use luxe to measure light intensity because that is a more accurate measurement of how our eyes perceive light overall and that's what lux meters were developed for.

    From what I found MH/HID and LED's provide more intense light further away and with wider coverage than HPS or LPS lamps _ and coverage is an important consideration as others have said. Coverage combined with intensity means you need more lights if your coverage and intensity at specific distances are less than other types of lights. Lux meters should work as well as lumen meters for lamps because the light they produce at various distances and coverage is more consistent.
    The coverage of LED's is based mostly on the pattern and strength of the diodes.
    LED's don't need a hood or glass and have different strength diodes and/or diodes that produce different coverage so lumen measurement is really the only accurate way to measure light output.

    LED's also produce more intense light at close distances but they also produce deeper light penetration (that is why you need to be very careful with light placement) and why a meter that measures lumens is more accurate than ones that measure luxe_ for those using LED's.
    Lamps produce more even coverage at a specific distance and intensity falls off faster so LED's may be the best choice if you aren't able to get all your plants at the same height. If you can achieve that, then lamps might be the best way to go.

    The big question I'd like to know the answer for is what's the optimum lumen/luxe output for the most productive results at various stages of development?
    Anyone come across anything along those lines?
    There must be some experienced growers who have researched this_ especially commercial growers.

    One things for sure_ find your sweet spot for what strain you're growing. Start with your lights a bit further away than recommended and then move them closer an inch at a time every 3 days or so, watching for any signs of light burn every day. Be very careful the first ten days from emergence if growing from seed.
    From the 3 grows I've done with 6 different strains it seems that they have different needs or tolerances for light, at least to some extent.
    When I compare plants grown by different folks with different types of light it seems that genetics, environment and the time it takes for them to mature affect production
    as much or more than light distance as long as your plants don't stretch too much or get light burn.

    Comment


    • #17
      Regarding the Lux meter, I traded out for the one used in the tutorial and the results were the same. I'm still confused because the numbers are so low: 21k about 6 inches from t5, 29k about 20" from the 1000 watt hps, and only 16k 3.5 feet from the supposedly spectacular 1000w HPS DE?

      I removed the glass on the 1000 watt hps, as suggested, and had to get a foot away from the bulb to get to 65k. I do hope the HPS is confusing the meter and it's not this low.
      Regardless, the DE is much weaker at the distance required so I'm confused about what all the fuss about these bulbs is.

      Comment


      • NebulaHaze
        NebulaHaze commented
        Editing a comment
        I don't think it's the HPS messing up the readings, as lux meters works for all the HPS lights we've used. Just curious, how old is your bulb and ballast? Usually HPS bulbs need to be replaced every 2-3 grows before they start to lose their brightness. Ballasts are usually more reliable, but it's still possible that it could be broken in some way. But it's really odd, you should definitely be getting FAR higher readings from a 1000W HPS

    • #18
      I have a handful of lights and the one I tested has a brand new hortilux bulb. The others have older bulbs but are in the same ball park as far as the reading goes (slightly lower). The ballasts are about 6 months old and are set at 1000. It's perplexing. What reading do you usually get around 1.5 feet from hps? What should it be?

      Comment


      • #19
        I'm not sure the exact distance, but my 250W is close to 65k lux at 1.5 feet, so I believe it should be much higher with your 1000W.

        I figure there's only a few places that could be having trouble:
        • Lux meter - you've tried two different ones so I doubt it's this
        • Bulbs - you've tried multiple bulbs and they're all getting the same reading
        • Ballast - This is the only thing left I can think of. Does it have a setting to adjust the strength, possibly? I know some can be adjusted to 25%, 50%, etc with a switch.
        • Electricity from the wall? This seems really unlikely to me, because I doubt the ballast would run properly if there was an electrical problem.
        Do you live near a hydro store? Is it possible you could bring in your ballast and have them test it for you? I think they would be able to confirm one way or the other whether it's actually the ballast. What a perplexing problem!

        Comment


        • francis pharmer
          francis pharmer commented
          Editing a comment
          Thanks! I'll try to test the ballasts/ electrical current. The ballasts do have settings for 600-750-1000 and keep blowing so maybe they are defective. OR perhaps the light is getting eaten by the space around it as it's not being fully utilized. there's silver insulation on the walls but it's not as reflective as mylar or bright white paint. I'm determined to figure this out!

      • #20
        I still think that PAR is the light reading we should be using NOT lux.

        Comment


        • #21
          Originally posted by Stewart169 View Post
          I still think that PAR is the light reading we should be using NOT lux.
          Although I agree, there aren't really affordable pieces of equipment that accurately measures the number of photons you get in the PAR range. Real spectroradiometers cost thousands of dollars! Even the more-affordable-but-still-expensive quantum sensors can be up to 18% wrong with LEDs/light emitting diodes based on which light source they were calibrated for (more info).

          In general, lux is close enough to estimate, at least for most types of light besides LEDs For LEDs, you need a real spectroradiometer that is designed to measure light from unusual light sources like LEDs. I hope that helps!

          Comment


          • #22
            Apogee has tables to show the offsets from factory preset calibrations. For a couple hundred dollars they are not cheap but how many of us spend more than that on stuff we don't end up needing? Plus if they help us grow better medicine its worth it down the road. They are calibrated from the factory for sunlight or fluorescent lights and like I said they are cross referenced to tables for the difference. For electric lights its only a few percent. I just decided as a hobby personal small grower to geek it a bit and a decent meter like the Apogee is far more accurate than a generic lux meter.
            When I see major schools and research departments of the universities referencing PAR and using these very instruments for there research that get people doctorates in agriculture I will give them some weight of opinion. They don't use lumens anymore. If I had been using lumens and light meters in the past Id probably consider staying with them. However as a new grower starting from scratch I will go with what the guys and girls who work on the same campus that sent people to the moon.

            And I have to give you a big thanks for the manifold tutorial. I am on my first one and just did the final trim on a couple of White Widow girls. The pics are just great for a point by point lesson.
            Last edited by Stewart169; 11-21-2016, 04:51 AM.

            Comment


            • #23
              Retract statement.
              Last edited by Tersky; 11-30-2016, 04:05 PM. Reason: False alarm
              Current Grow:
              Auto Sour Diesel and Ak48

              Comment


              • #24
                Click image for larger version

Name:	IMG_6325.JPG
Views:	1
Size:	980.6 KB
ID:	54678 I've only grown with 3W LED panels, so my experience is limited to that. I have tried 3 different brands too, and have experienced different results with each brand.

                I never go closer than 18" with any brand; however, the manufacturer Lush Lighting claims one of their panels can be as close as 12". I have a Lush Lighting panel, but I haven't used it yet. I'll provide an update after testing it out myself.

                My favorite is Hydroponic Hut's ProGrow light. It seems they're moving away from 3W LEDs, but their 3W panels that are still available have never burned a bud for me at 18". My girls have probably even been within 14-16" of the panel, still with no bleaching or burning.

                My worst LED experience was with an Advanced Platinum panel (whichever one is around 300W). At 20" plus, I was getting burnt leaves; plus, the arrangement of their LEDs creates three different color zones, which makes your plant grow differently in the center than out at the edges. Buds were small too. I'm trying the panel again now that I removed the cone reflectors around each LED. LED panels without those cone reflectors have more of a flooding effect, rather than a spotlight. There's probably less light penetration now, but I can keep the light at 18-20" without burning anything.

                Maybe the Advanced Platinum panel works well at 36" above the canopy, but I was just following the manufacturer's recommendation.

                Ive also tried an Apollo panel, but it made so much heat, so I didn't bother with it too long.
                Last edited by Monkey Allen; 02-10-2017, 10:20 PM.

                Comment


                • NebulaHaze
                  NebulaHaze commented
                  Editing a comment
                  Wow, thanks for the wonderful review! Everyone loves hearing experiences from people who've actually grown with LEDs! Especially if you've tried different models to compare!

                  Just curious, we're you using this LED model from Advanced Platinum? http://amzn.to/2lfQsjo

                  It's interesting you mentioned the heat with Apollo LEDs. I've heard someone else mention heat before. If you remember, what size/model were you using?

                  Thanks again for your write-up! I think it may be helpful to other growers

                • Monkey Allen
                  Monkey Allen commented
                  Editing a comment
                  Yes, that was the Advanced Platinum LED I used.

                  So far I'm happy with its performance now that I took the reflectors off (no leaf burn at 18-20" above the canopy). My girl is still in veg, so we'll see how she continues through bloom. Fingers crossed!

                  The Apollo LED I used was the 240W model.

              • #25
                Originally posted by ZigZag View Post
                Measuring Lumens or luxe is really the only way to accurately measure how much light is reaching your plants. For various reasons- space, electricity draw, etc. I chose to try LEDs.
                Measuring watts with LED's is not really a good way to measure light output, really it only a measure of the amount of electricity required to run your lights. After my previous post about LED's I decided to use a light meter to measure the light at the tops of the plants and midway down (a distance of about 12-15" average for 6 plants. The intensity of the light measured 12" from the tops varied (anywhere from 50-90% of the light measured at the top), but at the tops it was consistent. I used an old light meter (photographic) to take these measurements (it measures lumens) and it seemed to be pretty accurate.

                For those of you who have a "geeky" side here's some more info_
                An article I ran across published by some researchers who were comparing how much light is produced by various types of lighting and how that light was actually perceived by the human eye provided the following information (I'm not going to include the comparisons between lumen output and human perception because its not really relevant to plants)_ so here's what they found_
                LED's produce about 100 lumens/watt
                HID/MH produce about 90 lumens per watt
                HPS produce about 110 lumens per watt
                LPS produce about 130 lumens per watt.

                These measurements are in lumens (which measures direct light output and is what my light meter measures).
                However meters that measure perceived light at different distances and coverage patterns use luxe to measure light intensity because that is a more accurate measurement of how our eyes perceive light overall and that's what lux meters were developed for.

                From what I found MH/HID and LED's provide more intense light further away and with wider coverage than HPS or LPS lamps _ and coverage is an important consideration as others have said. Coverage combined with intensity means you need more lights if your coverage and intensity at specific distances are less than other types of lights. Lux meters should work as well as lumen meters for lamps because the light they produce at various distances and coverage is more consistent.
                The coverage of LED's is based mostly on the pattern and strength of the diodes.
                LED's don't need a hood or glass and have different strength diodes and/or diodes that produce different coverage so lumen measurement is really the only accurate way to measure light output.

                LED's also produce more intense light at close distances but they also produce deeper light penetration (that is why you need to be very careful with light placement) and why a meter that measures lumens is more accurate than ones that measure luxe_ for those using LED's.
                Lamps produce more even coverage at a specific distance and intensity falls off faster so LED's may be the best choice if you aren't able to get all your plants at the same height. If you can achieve that, then lamps might be the best way to go.

                The big question I'd like to know the answer for is what's the optimum lumen/luxe output for the most productive results at various stages of development?
                Anyone come across anything along those lines?
                There must be some experienced growers who have researched this_ especially commercial growers.

                One things for sure_ find your sweet spot for what strain you're growing. Start with your lights a bit further away than recommended and then move them closer an inch at a time every 3 days or so, watching for any signs of light burn every day. Be very careful the first ten days from emergence if growing from seed.
                From the 3 grows I've done with 6 different strains it seems that they have different needs or tolerances for light, at least to some extent.
                When I compare plants grown by different folks with different types of light it seems that genetics, environment and the time it takes for them to mature affect production
                as much or more than light distance as long as your plants don't stretch too much or get light burn.
                Looks like HPS is the way to go looking at your ratings on the lights

                Comment


                • #26
                  I originally got LED's because they were suppose to produce less heat but they really don't when you compare them watt to watt_pretty much the same. For the grow I just started 3-4 weeks ago I decided I was going to trade out the LED's I had for either an LEC or a white light LED. Reason is I have to work in the room where the grow closet is and can't always close the door so the red/purple of the LED's got to be too much of a pain. Had to wear those glasses to work with the plants and the red/purple light was making it difficult to judge color on my monitors. A grower in our town has a bunch of LED lights by Fluence which he was raving about. He uses the "spider' model for seedlings and young plants and then at about 3 weeks he moves them under the VYPRx lights that are more powerful and have better penetration. He also has LEC lights between the VYPRx lights. I decided to get the VYPRx because two of them fit into my grow space perfectly to cover the area with completely even light from wall to wall. The PAR from these lights is really impressive. They do have some green in their spectrum though so you need to get more watts to get as much blue and red light as you would with regular LED's. The light they produce though is really nice, easy to work under and the mol/m2/s is very impressive.
                  However_ warning_I probably wouldn't recommend the VYPRx for seedlings, even at 4 feet above they were probably a bit too much. Next time I will use a lamp light for that stage.
                  But now that the plants are about a foot tall and starting to really get bushy they are loving these lights. Much easier for me to work in the same room with.
                  If I had room I think i'd maybe di the same thing_ mix the LED white lights with the LEC_and use a veg lamp and a flower lamp in the LEC. For the last four weeks of flowering I'm going to add one of the older LED's and just use the flower light to add in a bit more warm light. Cheers, happy growing!

                  Comment


                  • #27
                    I've got a question about lights that I have been trying to find an answer for on the net, and it seems to be a bit confusing. Any how, I notice alot of people talking about wattage, isn't wattage the driving force for a light? It doesn't seem to have a bearing on the light itself, when I say light, I am referring to the lumens of light that is produced by the wattage being pumped into the light fixture. Say for instance, you have a 1000W LED light that can produce 150000 lumens, but yet another 1000W LED that can only produce 100000 lumens, but yet they are both rated 1000W and draw the same amount of power. See what I'm saying? It makes me wonder which would be a more accurate method for determining which lights to use.

                    Comment


                    • Flexy123
                      Flexy123 commented
                      Editing a comment
                      Wattage (that is, how much power the light uses) MEANS ABSOLUTELY NOTHING. I am still stumped how some growers are still using wattage in classifying lights, but this is likely because not too far back 400W/600W HPS lights etc. had been standard, so one could compare 400W lights to 600W to 1000W lights etc.

                      But now, we also have LEDs, and/or other types, so "how much watts a light requires" means NOTHING. Worse, manufacturers often deliberately deceive/mislabel their lights so that the wattage of a light means even less.

                      What counts is really the output of a light, oh wait, not even that, but how much light is actually hitting your plants.

                      "Lumens" is also meaningless, it's a measure of light how the eye perceives it, this includes green from the spectrum which plants don't even use.
                      For plants, PPF (and PPFD) are the only meaningful variables together with others like DLI (Day Light Integral) which can be calculated from PPFD.
                      (DLI, simply spoken is how much light a plant needs/gets over a day).

                      Why is this interesting?

                      Because for some plants, the needed DLI (or PPF) for best results are known.
                      Like here, where you can see a nice table for DLI values.

                      https://www.extension.purdue.edu/ext...ho-238-b-w.pdf

                      Obviously they don't have weed in the list, but Roses/Peppers are the ones with the maximum light requirements on their list. Of course we know that weed in flowering needs even more...

                      PPF (which is the light output from a given light) is also interesting because with SOME lights we actually know the specs and KNOW how much PPF/PPFD they can produce, given a certain wattage. For example, there are tables on the net how much the CREE LEDs produce, at what wattage. Means you can build a fixture with LEDs where you know the theoretical PPF!

                      (And, of course, when a reputable light manufacturer actually provides real measurements how much PPF their lights produce)

                      This is cool to know..because we KNOW the PPF requirement for weed,which is 800-1000 PPFD for flowering (above 1000 PPFD doesn't make too much sense because you will be getting diminishing returns), and for vegging much less, like 250-300 PPFD.

                      However - here the little caveat: You can in theory calculate how much PPFD (light, basically) your fixture produces, but that's of course not everything. Because it doesn't take into account distance to your lights, reflective walls, things like lenses etc.

                      What counts is really how much light really HITS your plants. And this can only be measured, but NOT with a lumen meter, but with a PPF meter.
                      (And this measurement is also not done just once, under one plant, but usually it's done in multiple spots in a grow room, and then an average is taken).

                      Sorry for getting excited there and writing all this...but you see this is a fascinating hobby and it can be very involved
                      Last edited by Flexy123; 10-10-2017, 02:41 AM.

                    • Flexy123
                      Flexy123 commented
                      Editing a comment
                      Well you can at least calculate how much a fixture can "in theory" produce, so you have a basis to work with. (Say, you build a light with X COB LEDs where each can output X PPFD at whatever wattage). This could help you get a first idea, say if you build a light. Say, you calculate that your fixture can only output 300PPF, you know for sure it won't ever be great for growing. If you calculate your light can output 1000PPF, it could give an indication that the light will be "ok" or should be ok, "+/-". (Of course the real light your plants will be getting will always be less than the theoretical specs). The good things about CREE (and other good brand LEDs) is that the specs of the LEDs are known, so people can plan and "sort of" calculate what type of lights they need.

                    • NebulaHaze
                      NebulaHaze commented
                      Editing a comment
                      "Wattage (that is, how much power the light uses) MEANS ABSOLUTELY NOTHING. I am still stumped how some growers are still using wattage in classifying lights"

                      We use it because it's an easy way to get a ballpark figure if you know the type of light. Like you said, it's easy to compare HPS to HPS purely with wattage. Same thing with MH, CFLs, T5s, LECs, etc. Even though it's not a perfect estimate, there isn't a whole lot of difference in light output based on the brand or manufacturer. It's pretty much like comparing apples to apples.

                      But like you said the difference between models of LEDs can be larger, so it's much harder to compare them directly than the other types of grow light. The form factor makes such a huge difference in how you use the light to get good results. That being said, wattage (actual draw from the wall, not any meaningless "equivalent" rating) will still get you 80-90% there as far as estimating yields, even with LEDs. There are differences between models but not enormous ones at least as far as purely yields as long as you're using the light properly.

                      At GWE, we've learned from our readers that LEDs on average seem to produce 0.5g/watt for beginner growers with a medium-to-good grow. Some models are more suitable to certain setups than others, and many growers beat those numbers with skill and a good environment, but as long as you're buying high-quality equipment (not cheap, broken lights that don't work properly), the wattage can actually give you a pretty decent ballpark estimate. After that, your yields have a lot more to do with what you're doing as a grower, your strain and learning how to use that particular model of light to its fullest. With some growers who have mastered their lights and environment, you'll see 1g/watt or more with LEDs.

                      Some people like to really dig deep into the nitty-gritty, and people like you are the pioneers that forge the way. But when we're doing these sort of standard wattage comparisons, it's aimed more at the casual grower who is just trying to figure out whether they should expect 3 ounces or 10 ounces from a light. With all the marketing mumbo jumbo it can be really confusing to figure out what you're actually getting, especially if you're a first-time grower and don't want to have to become a light scientist

                  • #28
                    Originally posted by BillyKidd View Post
                    I've got a question about lights that I have been trying to find an answer for on the net, and it seems to be a bit confusing. Any how, I notice alot of people talking about wattage, isn't wattage the driving force for a light? It doesn't seem to have a bearing on the light itself, when I say light, I am referring to the lumens of light that is produced by the wattage being pumped into the light fixture. Say for instance, you have a 1000W LED light that can produce 150000 lumens, but yet another 1000W LED that can only produce 100000 lumens, but yet they are both rated 1000W and draw the same amount of power. See what I'm saying? It makes me wonder which would be a more accurate method for determining which lights to use.
                    Seems that alot of the confusion regarding grow light is lumens-lumens are for humans, not plants. A better unit of measurement is PPF and PPFD. These give you an actual power output that the plant can use(PPF) and how well the lamp is designed to distribute that light over a given area(PPFD). With THOSE bits of info it's [possible to compare apples to apples.
                    WHAT???

                    Comment


                    • gbauto
                      gbauto commented
                      Editing a comment
                      What I'm saying is that the fixtures ability to produce a given quantity of light is only one part of the package, being able to evenly distribute that power over an area is also important.

                    • BillyKidd
                      BillyKidd commented
                      Editing a comment
                      I found a chart for the grow light that I have.
                      1000W with a 90-120 lens. It recommends for Bloom 59". So that's probably going to be where I place it. For veg I have a different light I'm going to use.
                      For this particular light at 59" height it has a Lux of 1692 & PAR of 1170 and m² of 5.0

                    • Flexy123
                      Flexy123 commented
                      Editing a comment
                      Yes if a grow light vendor advertises a LED with Watts...or Lumens...RUN
                      Any reputable vendor of good grow lights should provide PPF/D measurements. Anything else is really useless/misleading.

                  • #29

                    Comment


                    • #30
                      Wattage (that is, how much power the light uses) MEANS ABSOLUTELY NOTHING.
                      It means how much heat is produced. As I understand it, the actual power consumption by the device in Watts is directly proportional to heat released in BTUs.

                      This is of course no help in determining light issues, but it is useful in calculating your cooling needs.

                      Fake wattage claims from vendors based on imaginary equivalencies are of course no help at all for anything.
                      First-time California outdoor medical backyard grower -- Aurora Indica Feminized plants in soil.

                      Comment

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