PAR, PPFD, DLI and other technical information

@Covertgrower @dbrn32 @PremiumBudzBlondie

Hi all,
i have downloaded an app for my Iphone called KORONA it measures the LED lights in ppfd DLI and LUX its pretty cool app, at least i think it is,
so here is my problem, a web site i have been reading that talks about all this is describes all these things, unfortunately it isn’t straight forward as i would expect or hoped, as you can see from the pics i uploaded none of the readings are Expressed in μmol/s.m². and the graph on the web site said cannabis requires

please see attached information
typical μmol/s.m² values for horticulture lighting?
Min Max Typical
(μmol/s.m²) (μmol/s.m²) (μmol/s.m²)
Cannabis Vegetative growth 280 450 350
Cannabis Flowering 650 1,000 850

the 3 pics i uploaded are DLI over 12 hours
the PPFD and the Lux
which pic is the reading i use to compare to these numbers expressed in μmol/s.m² do i need to use one of the numbers in the pics and apply a formula to it? or is it straight forward and i just am not smart enough to comprehend it? could it be as easy as the number expressed in μmol/s.m² is equal to the ppfd,

am i reading to deep into this and should i forget trying to understand the physics involved

please advise

You are taking a single point measurement a d that is what the app is generating data off of. Unfortunately, that only tells you what is happening at the point of measurement. You
need to calculate ppfd average of your entire space and run the formula for DLI based on that.

For what its worth, I would probably back the light off some before doing that.


I downloaded a similar app, haven’t tried it yet. I’ll look that one up too.

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Phones are pretty worthless as light meters because they lack the diffuser that a real meter has.

Much of that information might be available from the manufacturer. Remember also that distance from the fixture matters a great deal when taking these measurements. Any real accurate tests for lighting is normally conducted in a sphere, which is super expensive and not something available to the common man.

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i will be honest and say i probably wont go through all that,

i will and have taken readings at multiple points and moved and adjusted the lights height and spacing based on the readings to try to get the readings higher, but i still am confused on the whole μmol/s.m² can i safely say if i have my PPFD up into the 4 digit range that my μmol/s.m² will be in the typical range, or am i confused all the way around and the PPFD is the name and the
μmol/s.m² is just the unit of measure for PFFD

i was hoping to just figure out how to use the info provided by this app at the single point of measurement,

i used the formulas and computed the DLI based off the PPFD and it was really close i bet the slight differance is from the formula and the APP reading is due to taking and moving phone to change the settings to read dli instead of ppfd,

I was getting confused with all these measurements. I deleted my phone app. Now I just look at how my plants are doing. All’s I know is that my plants BLEW the fuck up when I switched to quantum boards That’s all I need to know.

The problem is that it doesn’t really matter if your ppfd measurement is over 1000 at one point if it’s significantly lower at any other point. As far as quantifying light intensity levels to know if your plants have enough light or you should consider supplementing co2, that needs to be considered across your entire canopy. Like corner to corner and wall to wall, not just at a couple of points directly underneath your fixture.

That’s why I don’t even bother with those app’s or even a par meter. If you have an estimate of the total radiometric flux of your fixture you can calculate ppfd average by amount of light over area in m²

Ok good to know and you mentioned C02, which happens to be one of my next inquiries, being that co2 is such a dangerous gas sort of a silent killer how safe is it to use in a tent? Will the co2 produced from fermentation of wine be an adequate amount for instance if my wine making kit was next to my tent and I piped the vent gas into the tent via tubing would that amount to any thing worth while, my wine kit will produce a couple cubic feet of gas per hour when it’s at peak fermentation? And that last about 2 weeks obviously I would not be able to do it constantly, but some is better than none correct

Probably not worth the effort. What size is your grow space and what do you have for lights?

I downloaded that app too. First time indoor and new light. So other than reading how everybody is setting there’s up. I was totally lost. Now just 3/4 lost ha. Kinda gave me a insight of around about were I need to be. I’m at 3 weeks and all looks good now. If you swipe to left it shows ppfd.
What I didn’t get was there are 2 led on there. 1 for white led and other for red. When it’s on white ppfd goes down about half of when on red. So I guess that’s for white with red led. Checked with a recommended app and was just a couple numbers off. I’m a green horn so if anybody has any info on that please let me know. Thanks.

sorry for such a late response, i am not big internet person
so my grow space for flowering is 4 x 8 and i have 5 of the 240Watt HLG quantum fixtures 3500K w\ 660 nm
configured like = I = each of the equal signs represent 2 lights and the cap i represents 1 light
thats about the only way i could figure to describe it i also have a home made DIY light i am thinking about swapping out with the i light it is made of 9 of the 50 watt sun boards with 450 watts of power and then 2 of the red booster boards that have separate 80 watt supply, i have been using it in my Veg tent, and i use 4 of the sun boards at each level of my propagation tent

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Sounds like a great setup. I’m not sure I would piss around with the co2 though. Cost and labor involved with implementing and maintaining doesn’t usually increase returns enough to justify it.

thanks and i agree the Co2 sounds like a pain and with all the climate change activist complaining about co2 i assume there is already plenty in the air already

The concentration of carbon dioxide in Earth’s atmosphere is currently at nearly 412 parts per million (ppm) and rising.

Typical occupied spaces with good air exchange have carbon dioxide levels between 350 and 1,000 parts per million. Since humans exhale carbon dioxide as part of respiration, overcrowded houses may lead to elevated carbon dioxide levels.

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that sounds like a lot… is it enough for growing? what is the recommended levels for plants

I was answering your post:

I have no idea about using Co2 in home grows, except it seems to be generally acknowledged as a waste. Co2 is best used in grows where everything is dialed in and controlled exactly, such as in large scale commercial grows.

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