MindSoup Posted February 13, 2021 Share Posted February 13, 2021 Spamming a bit here, admin feel free to delete the previous topic in the general light section. Think this might be a better place to ask. As you might already know I grow in a tiny box (35x55x75cm) with an invisible sun ish100 b/r, so I get really close to my light. My first run in the box I ended up with buds just cms away and got some bleaching on bud tips. So I'm keen to try and learn a bit about light intensity, it seems there are wildly different numbers floating around. What I'd love to know is the maximum PPFD/DLI at canopy level that a cannabis plant can take before stress occurs at ambient CO2 levels (no supplementation) with all other variables optimal. After a few hours of reading and watching I've found some useful tools on waveform lighting's website for converting LUX to PPFD and PPFD to DLI and found some good videos by Bruce Bugbee (Apogee Instruments) on the general subject, but nothing from a fully legit source specifically answering my question. Has anyone else gone down this rabbit hole? 3 Link to comment Share on other sites More sharing options...
Punk#1 Posted February 13, 2021 Share Posted February 13, 2021 Pretty sure Bugbee said the DLI gets up to 60 in some places in the US and the plants love it. Im assuming thats without elevated co2. Bugbee is gully legit as it gets imo.. I think we just need to wait for the science to catch up to find out, because nobody really knows for definite. Just try to read the plants 2 Link to comment Share on other sites More sharing options...
MindSoup Posted February 13, 2021 Author Share Posted February 13, 2021 (edited) 48 minutes ago, Punk#1 said: Pretty sure Bugbee said the DLI gets up to 60 in some places in the US and the plants love it. Im assuming thats without elevated co2. Bugbee is gully legit as it gets imo.. I think we just need to wait for the science to catch up to find out, because nobody really knows for definite. Just try to read the plants He does say that but doesn't really clarify if thats with CO2 supplementation or not. That same video he says a maximum of around 1500 PPFD which is about 500 below a GLI of 60 but still way higher than other people are stating. I'm wandering if there are any other studies more specific about CO2 levels correlation to maximum/optimal DLI, or if someone in my situation has had a head start on figuring these things out. I could just wing it but that's inefficient and will cut yield, and when you have 0.2m² to play with every gram matters. It could be a few crops before I can dial it in by trial and error. Edited February 13, 2021 by MindSoup 1 Link to comment Share on other sites More sharing options...
MindSoup Posted February 13, 2021 Author Share Posted February 13, 2021 Maybe @diyleduk might have some insight? I apologize in advance for not using one of your products; you where all sold out at the time. 1 Link to comment Share on other sites More sharing options...
growinggold Posted February 13, 2021 Share Posted February 13, 2021 Do you think strain variety will have place to play in this? Are some plants more forgiving to extreme light more so than others? Just thinking stoned aloud here. Great subject. I guess it case of going slow and dialling up rather then down. I tried to do this on my current run. But one of my 6 strains (also the biggest) has started to show bleaching at 240w I had planned up take to 280 but I'm now thinking I should go back to 200w. I was also thinking/ read somewhere growers move there led to max height and power at flip and hope forces the girls into check. Rather then slowly taking the power W and height higher slowly. I guess this is all experience and expernination with your groom. In sure Bruce has special instrument up his sleeve to have us all okay. I hope. 2 Link to comment Share on other sites More sharing options...
Punk#1 Posted February 13, 2021 Share Posted February 13, 2021 @mindsoup no he doesnt state wether that's with elevated co2 or not but its outside so i think it goes without saying its not with elevated co2. 2 Link to comment Share on other sites More sharing options...
MindSoup Posted February 13, 2021 Author Share Posted February 13, 2021 11 minutes ago, growinggold said: Do you think strain variety will have place to play Actually that's a good point and I think it would. I was watching a video with kevin jodrey talking about some strains actually preferring shade so some would definitely have a higher tolerance than others, however I think most indoor strains would be quite adapted to high levels of light. He also talked about old skool strains not doing as well under LED because they where bread using HIDs. 11 minutes ago, Punk#1 said: @mindsoup no he doesnt state wether that's with elevated co2 or not but its outside so i think it goes without saying its not with elevated co2. True maybe I should try and email him and get him to clarify, I bet he'd have an answer for us. Just double checked and I'm not even calculating PPFD/DLI properly. Been using migros guide for converting lux readings from an app but my light is 5k and his guide is for 3.5k/4k he does have another guide using a stand alone meter with a bit more info so maybe I'll buy one of them. 1 Link to comment Share on other sites More sharing options...
Punk#1 Posted February 13, 2021 Share Posted February 13, 2021 (edited) @MindSoup Do you an an iphone? If so try the corona (ikr?) app it measures ppfd/dli etc its free but you need to pay a fiver to unlock the light profile your using on the app How accurate is it i dont know but it seems close enough for your average bedroom grow imo For my CMH @24" im getting about 400 ppfd for my seedlings according to the app which seems legit E2a- I was at roughly 24" already anyway going by advice from folk on here so it seems people can get lights dialled in even without fancy apps and quantum flux interdimensional transwarpfeild meters Edited February 13, 2021 by Punk#1 1 Link to comment Share on other sites More sharing options...
MindSoup Posted April 21, 2021 Author Share Posted April 21, 2021 On 13/02/2021 at 3:19 PM, Punk#1 said: @MindSoup Do you an an iphone? If so try the corona (ikr?) app it measures ppfd/dli etc its free but you need to pay a fiver to unlock the light profile your using on the app How accurate is it i dont know but it seems close enough for your average bedroom grow imo For my CMH @24" im getting about 400 ppfd for my seedlings according to the app which seems legit E2a- I was at roughly 24" already anyway going by advice from folk on here so it seems people can get lights dialled in even without fancy apps and quantum flux interdimensional transwarpfeild meters Think I somehow missed this comment, thanks mate I'll have a look Link to comment Share on other sites More sharing options...
MindSoup Posted April 21, 2021 Author Share Posted April 21, 2021 (edited) Dang, its not on Android. But many others are, Migro seems to recommend "light lux meter" and has done a handy conversion chart, should be fairly accurate, just slight discrepancies from phone to phone. Edited April 21, 2021 by MindSoup Link to comment Share on other sites More sharing options...
Keye Posted April 22, 2021 Share Posted April 22, 2021 I get it; I like the science. I started on micro grows and only every got to a 400w grow before I'm now scaled back in a 31x60x90 box and I am itching to get them closer. I don't think it matters. Take your plants as close to the lamp as you can; if they stress, move them away. The next plant will be different. 1 Link to comment Share on other sites More sharing options...
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