Have you seen the work out of Utah State University by Dr. Bruce Bugbee? Agree on diminishing returns at atmospheric CO2 levels, but they've grown plants well into the 80 DLI range and they do better, albeit less better, than 60. Assuming you can have perfect control of everything, the upper limit is way above 60.
Bronze spots and fan leaf dying
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No, I have not seen that study from him can you give me a link? I love that guy but he really really wants to sell me a meter.
This is not a primary source from Dr. Bruce, but they use some of his data here. The one thing I noticed here is that the outdoors DLI May-July is above 80 for the location they cite, which is not to make any statement about the viability of this idea indoors, but generally speaking outdoors cannabis is getting 70+ for most of the mid-summer.
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"If you want to maximize yield you need to push it hard with light"...Dr. Bugbee Utah State Whether you grow in a tent or commercial facility, every serious grower should know Dr. Bruce Bugbee’s work on cannabis. From lighting to soil. His plant work is funded by NASA and he has decades of...
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James Faust is the leading Horticulturalist specializing in DLI at MU and this is from his interactive DLI calculator. This is the hottest month and very little of the USA ever sees 65 DLI. and then only for a short time not all summer.
myutk.maps.arcgis.com
Story Map Series
This story map was created with the Story Map Series application in ArcGIS Online.
James Faust is the leading Horticulturalist specializing in DLI at MU and this is from his interactive DLI calculator. This is the hottest month and very little of the USA ever sees 65 DLI. and then only for a short time not all summer.
View attachment 1284882
Story Map Series
This story map was created with the Story Map Series application in ArcGIS Online.
Yeah I see that the data there is lower than the link I shared.
That doesn't convince me that you can't push a plant beyond 60, the video Dr. Bruce has on youtube explains that although the returns diminish beyond 60, the curve maintains a positive slope. I'm making a technical argument about an extreme edge-case, definitely not a recommendation for anyone here, but to say cannabis can't or won't grow beyond 60 is perhaps at best a conjecture, not a statement about experimental evidence.
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IMPO mamouthlighting .com is not an empirical source for DLI information. The latest scientific study I can find has 65 DLI as the highest measured number.
The thing is 80 DLI is not realistic even if someone measured that somewhere it is an anomaly. 60 DLI is overkill and a waste of energy input on an indoor cannabis grow which is the topic here. My statement that cannabis needs 28 DLI as a minimum with 40 DLI being a good target still stands as good science.
The thing is 80 DLI is not realistic even if someone measured that somewhere it is an anomaly. 60 DLI is overkill and a waste of energy input on an indoor cannabis grow which is the topic here. My statement that cannabis needs 28 DLI as a minimum with 40 DLI being a good target still stands as good science.
Please understand, there's no disagreement on my end as far as it relates to advice on the forum, you're exactly right. I suspect the verdict is still out in terms of a highly controlled laboratory setting, though, and all things being equal, current research indicates it would offer returns, albeit at a much diminished rate beyond 60. I'm only making this point to highlight how truly miraculous the cannabis genus is, in essence there's no known limit to the growth we can push on these plants; they're able to perform well above similarly high-performing crops like corn!
A follow up about the baby: she's still growing and looks like the buds are thickening a bit. Also trichomes are developing on sugar leaves all around the bud.
I'm worried about the brown spots going up nearby the flower. Yesterday I did the ManO'Green treatment for the second time (the first was made on 5th). I calibrated again the ph pen to be sure to do it right at 6.3.
She's now in early week 7, with an expected seed to harvest of 9 or 10 week. Anything to correct?
Cheers!
I'm worried about the brown spots going up nearby the flower. Yesterday I did the ManO'Green treatment for the second time (the first was made on 5th). I calibrated again the ph pen to be sure to do it right at 6.3.
She's now in early week 7, with an expected seed to harvest of 9 or 10 week. Anything to correct?
Cheers!
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Lots of great information being passed about... hopefully you've got the issues sorted and your plant makes a good recovery... but if that's 7 weeks old now I wouldn't expect it to be ready at 9 to 10!. Thats more like from when flowers show to harvest so you've got 5 weeks easily yet!. 
Hi everyone, new week new problem on the tricky fat Banana 
The plant is now 7 week old, I did the 3rd fertigation with 30% runoff at 30% strength of nutes. What I see is that those brown spots climbed up to the newer leaves, almost to the bud top. Moreover the latest sets of leaves have this purple/blueish color... I have seen that pictures of deficiencies resembling this symptom such as copper Def or molibdenum Def.
I doubt that a real deficiency is going on, at least a Def of micronutrients... But I ph-ed the fertigation at 6.3 every time, so I don't know what could cause a ph swing in the soil.
Maybe the ph pen is fucked up (that's why I ordered an Apera PC60) or the lemon juice/baking soda really have no effect on keeping the ph of the nutrient solution where it must be.
Any idea?
The plant is now 7 week old, I did the 3rd fertigation with 30% runoff at 30% strength of nutes. What I see is that those brown spots climbed up to the newer leaves, almost to the bud top. Moreover the latest sets of leaves have this purple/blueish color... I have seen that pictures of deficiencies resembling this symptom such as copper Def or molibdenum Def.
I doubt that a real deficiency is going on, at least a Def of micronutrients... But I ph-ed the fertigation at 6.3 every time, so I don't know what could cause a ph swing in the soil.
Maybe the ph pen is fucked up (that's why I ordered an Apera PC60) or the lemon juice/baking soda really have no effect on keeping the ph of the nutrient solution where it must be.
Any idea?
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