PAR vs. DLI for Autos

What’s the difference between these? Almost thought I had ya some then lol @MrPeat


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@Se7en Its two different breeders. Two different strains. I can’t vouch for Purple #1. I read their description and I believe Purps #1 would blow it out of the water. Its a creeper and she will hit all of a sudden out from left
field. Its so good that I would add it to each crop grow cycle and make their is plenty of amber. :+1:

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That light won’t be enough. Honestly save money for a HLG light. But @dbrn32 is the light guru.

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PAR and DLI are 2 different ways of measuring the same thing. Time is the only variable that differentiate the two.

I would go with the HLG 135 versus the Mars. You will be ensured that you are getting top bin diodes.

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I believe this light would only be around 100 true watts?

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I get ya! Thanks brother I’ll keep keeping an eye out for that purps for sure! Love purple strains they don’t come around too often round my way anymore

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Oh if you can, I promise it will surprise you and you should love this strain. One of my connections for concentrates even said it was mind blowing. And this kid smokes 10 times more than me and I have smoked over 300 strains. :joy::joy::joy:

I can’t upload photos till I get home. The old phone has all my pictures.

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A simple and easy explanation. If you do ever find the chart and can post, please do. Are either of these charts what you have?

The number of moles per hour, per m2, multiplied with photoperiod (the number of hours with that intensity) = DLI, Daily Light Integral

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Guess I can post on Chrome. Normally use duck duck go.


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Does it matter if you are getting the same DLI whether you are doing 12 hours or 18 hours of light? I have 2 autos in the same tent as photos and theyre on the 12 hr cycle now. Does it matter to the autos?

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Mathematically it wouldn’t seem so to me.

@MrPeat was explaining his experience to be contrary on this thread just yesterday. I haven’t grown enough of them to have practical comparison.

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In my opinion and experience, I do feel Autos do better on 18/6.

I say this because I have grown multiple Autos and all was different strains from Top Shelf Seed Companies and I always get 1 to 2 oz dried, cured and no stems. Every single time. Never fails.

I grow straight 12/12 start to finish. Now my Sativa plant’s absolutely love 12/12 start to finish.

@Underthestairs I have been saying this for awhile now.

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They won’t ship to me. Thank you tho. I tried to order seeds from the direct breeders website and none ship to the USA.

Because they had some strains I wanted but couldn’t order

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I am in Texas. Pretty strict. I order from Attitude Seed Bank. Even ILGM wouldn’t let me order. Who knows…maybe a glich.

We have to use a PO Box as we have no mail delivery which could be why I can’t order . :+1:

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Awesome thank you brkthetnil have a look at that site today! Pretty much any site ships to me in the UK, dunno how the law made sense of that :rofl::man_facepalming:t3:

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I need more help. I’ve checked my DLI and I’m confused. On my small autos, 5 weeks old, the DLI is 45. However, when I check my mature plants, almost ready to harvest, at their current PAR setting of 900 the DLI comes out to 70 something.

Am I really supposed to cut the light at harvest based on this chart? To get to this level, I’ll have to crank my lights down to the lowest setting. Should I raise the lights – or just change the settings?

When I turn the lights down enough to get the DLI into the 40s (high) I’m only getting 500 PAR for my plants.

And I’m curious about the highs and lows on this chart – the variance. Why do we go way up, then way down, then sort of mid level?

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The area in orange is most likely for those that supplement with CO2 The initial post reads an optimum (I’m assuming for regular growers who do not supplement with Co2) a DLI of 40.

“For Autoflowering plants the typical light cycle is 20 hours on and 4 hours off. This maximizes the time the lights are on while still allowing a few hours darkness for the plant to ‘sleep’ and metabolize. Because the day is longer the PAR intensity can be lower to reach the same maximum 40 DLI .”

If your not supplementing with Co2, your wasting watts (above 40 DLI). I personally keep it at 38 DLI max with great results. And only reach for that 38 DLI about 3rd or 4th week of flower and on. I’m trying the 20 / 4 light schedule at the moment at 450 PAR and am in veg. That’s about 32 DLI. So far so good.

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That chart represents photoperiod cannabis. To mimic nature, I wouldn’t think about it too much. Since Autos are subject to almost 24 hours of light in their natural habitat, I’d concentrate on keeping it easy and set it and forget it at a comfortable setting to your liking. One for Veg then one for flower. I know some growers who just blast it all the way from seedling to harvest at 40 DLI. I don’t have that kind of freedom with the electric bill. 500 PAR at 20 hours is near that 40 DLI, I think 550 PAR at 20 hours is 38 DLI.

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I am also confused about DLI in a sense. I made a post about it because we have wattage recommendations for space of a tent. But going off DLI our wattage requirements would be ALOT lower than people require or suggest. IE: I’m using an HLG 550v2 for my 4x4 becauze I was told that’s kind of minimum / perfect balance for a 4x4. Using DLI though Im nowhere near maxing out my wattage and could have got by with a light half the power. Especially if we follow the dli charts considering we will be lowering the power later. It doesnt make sense to me.

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To add to my response I checked my light today I’m at 283 watts out of my 480 available or whatever and I’m at 45 DLI. According to DLI charts I’m maxed and will only go down in wattage so theoretically a 250 watt light is enough for a 4x4 tent?