I use the PAR on the Photon app – why do so many of you use DLI?
Several things can cause purple stems and leaves, heat, cold, light burn, overwatering, high or low PH, transplant shock but that’s not in play here. Hard to narrow this down but the droop seems to be coming from overwatering. Can you fill out a support ticket and let’s get the duty expert’s involved 
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Because there’s a thread about using DLI and “how to”. It made lighting measurements very digestible, if not … perhaps overly simplified. If you understand PAR or ppfd, I think it operates the same. It’s just measurements of light intensity in different terms. @dbrn32 is the real guru to answer that question though.
Really depends on the context. Dli is nothing more than ppfd average with time component added. So it’s basically doing the same, just making consideration for how long lights are on. Ppfd average of 400 umols/s for 18 hours is same dli as ppfd average 600 umols/s for 12 hours. Depending on how you use this information could mean nothing substantial, or it could e the explanation to why so many people think it’s necessary to run autos on 18 hours or longer light schedule.
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What light schedule do you recommend bro for autos?
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How do I do that on here?
If you have high enough light intensity to hit good dli on 12 hours, i would just do that. If not, increase light time to a reasonable dli.
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-Blue Dream, ILGM, auto
-91 days
-Method: FFHF
-Vessels: Fabric pot, 5 gallons
-I just fed it at 6.4 and 850 ppm and it ran off at 6.3 and 800 ppm
-Runoff; I’m not sure what the meters brands are
-Indoor; 2x2 Spider Farmer tent
-SF2000; full spectrum
-200 watts
-18/6
-Temps; 74, 67
-Humidity; 45% all the time
-Ventilation system; Spoder Farmer 6” in-line fan, 350 CFM
-Frigidaire Dehumidifier
-Co2; No
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Ok… so if I run my scorp diablo at 800 ppfd for 12 hours. Would that suffice? What do autos need ppfd wise in 18 hours vs 12 hours to even out? Just trying to make sure I’m understanding you completely lol.
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Those numbers don’t reflect an issue at all. Overwatering could be the culprit but thinking after looking at the photos that she is magnesium deficient. Start adding epson salt ,it’s a great source that and sulfur
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I’ve been doing that (per your advice, actually) for the past week or so.
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Good, improvement may take a little while longer and bump the numbers up 1100, she’s eating from the last run off. I would skip the next water cycle and feed. I’ve grown 2 identical strains from the same batch and one could not get enough calcium and magnesium. She was a hog and the other took normal amounts
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What exactly do you mean here?
Are you on a feed then water then feed again rotation? If you just fed, let her go through the dry cycle then feed again.
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I thought that was what you meant but I wanted to make sure. So you are talking about back to back feedings, correct?
Yes back to back to get the PPMS back in the 1100 range for flowering. Wait until she’s dry though
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18 hours is roughly 33% more time than 12 hours. If you make 33% less light over 33% more time than dli is the same. Dli is just explanation of however you do this, mols per day is the same and such plant energy created is the same.
Its not hard to understand at all if you think in terms of photoperiod plants. Why does everyone say you need more light flower? It’s not because the plants physically require more intensity to flower like some seem to believe. The reason is because you flower photo plants on shorter amount of light time. Autos don’t typically require the reduction of light time to flower, which adds a different element. Running autos on long light schedule is just a way to increase dli without having more light intensity. In a broad general statement, it’s not better or worse to do one way or the other. Certain circumstances could make either way better than the others. If you’re dealing with other environmental issues increasing dli may do nothing for you. Some can push recommended dli levels and have great results. But it’s typically more complicated than just saying this amount of light for this amount of time because of all the other variables that change from grow space to grow space.
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That explanation was on point and a great way to consider the environmental conditions if you’re struggling with heat or even electric bills. Go 12/12 with lights off the hottest parts of the day
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What is a good DLI? I know what PAR I want at each stage. So, what DLI? If I could run lights less long, I’m 24/0, it would really help me with the heat during summer. Hmmm… gotta figure this one out.