Watts vs PPFD: which do you use?

[TorturedSoul]

Thanks, @Icemud . Even "back in the day" when HID lighting was pretty much it, we learned that lux/lumen was really only useful when used to compare two different (power) products from the same manufacturer, and sometimes not even then. Such things were wholly intended to be used for things such as illuminating human-occupied spaces, AFAIK. Living rooms, theaters, etc.

LED grow light manufacturer produces a light. The next year, *everything else* is the same, except that the manufacturer adds a few percent more red-spectrum diodes, remove an equal number of some other type in order to make room from them - and, even if the developer of a "PAR" phone app had specifically entered the characteristics of the specific product into a database (along with several hundred other products, which is probably not how they do these things), and the user has to select the light's brand/model from a big list... that data will now be wrong and, therefore, any "data conversion" that the app does in order to use the phone's sensor to... estimate the PAR output of that light will be incorrect.

That's why I don't bother. They can tell a person that turning the dinner knob counterclockwise will decrease the light's output, lol - but so can common sense and a basic electricity measuring device (e.g. Kill A Watt).

 

[Icemud]

and, even if the developer of a "PAR" phone app had specifically entered the characteristics of the specific product into a database (along with several hundred other products, which is probably not how they do these things), and the user has to select the light's brand/model from a big list... that data will now be wrong and, therefore, and "data conversion" that the app does in order to use the phone's sensor to... estimate the PAR output of that light will be incorrect.

Yep! You are spot on. LUX meters, phone sensors generally only use a single photodiode which reads all visible light and are weighted green heavy, therefore none of them will really be accurate at all.... and then add in the conversions based on spectrum and color temp and it will be nowhere near accurate.

PAR meters generally use 2-4 (or more) photodiodes set to read specific wavelength ranges so they get a much clearer picture of the photos emitted by a light, and are generally weighted even across the spectrum (to an extent as all PAR meters do have some error as well). PAR meters are made specifically for the purpose of measuring available photons to a plant. Are they perfect, no, but are they much more precise than lux meters and smartphones.. absolutely.

The best is a spectrometer which actually uses many sensors, each specific to a wavelength band to get a precise reading. These really should be used by all grow light manufactures at 3rd party labs to test their lights... Most LED companies are too cheap to spend the money on getting 3rd party lab tests with photogonio meter readings though.

At the end of the day... unless you are running a professional agriculture grow and setting up a grow facility the need for a PAR meter, or spectrometer is pretty much not needed... as any reputable light company worth their weight should provide 3rd party photometric analysis of their light outputs and data for their products. IF a company does their own "in house" testing, generally I don't trust it a bit as too many unscrupolous companies in the cannabis industry who are just full of greed. If a company in 2022 can't provide a PAR mapping done by a 3rd party then I wouldn't take the light company serious by any means... but really for 99% of the growers here on the forums, no meter is needed and a simple 4x4 PAR chart for the light of choice should be more than sufficient for planning out the lights output footprint.

 

[Mayne]

BUT, a photon flux, is still a measurement of intensity. And Lux reads as intensity. I personally think the PAR meter is the biggest Grower gimic in the industry. Especially after i bought a hydro farm PAR meter, and tested out lights that i knew for a fact, via utub videos of measurements, as a guild.

So, at the end of the day, its exactly a lux meter, but it just converts the readings into a "PAR" measurement, and charge 500% more.

So i configured a meter, thats gives a better "BallPark" figure then hydrofarms PAR meter, and just marking it up 110%,

 

[Icemud]

BUT, a photon flux, is still a measurement of intensity. And Lux reads as intensity. I personally think the PAR meter is the biggest Grower gimic in the industry. Especially after i bought a hydro farm PAR meter, and tested out lights that i knew for a fact, via utub videos of measurements, as a guild.

So, at the end of the day, its exactly a lux meter, but it just converts the readings into a "PAR" measurement, and charge 500% more.

So i configured a meter, thats gives a better "BallPark" figure then hydrofarms PAR meter, and just marking it up 110%,

PAR meters are not the same as Lux meters... they use different filtered photoelectric sensors specific to frequency band groupings weighted equally across the PAR spectrum.

Lux meters do not do this.

The "hydrofarm" branded one may be a scam but true PAR meters used in big AG and research like Li-Cor and Apogee use multiple filtered diodes to properly read light.

Yes at the end of the day, is light converted to a "signal" that then is converted to some type of reading.. yes.. but the way this happens is different in PAR Meters and Lux meters which is the difference.

 

[Mayne]

I know that Ice, What i said was, the HYDROFARM PAR meter, is a scam device, that converts LUX, and not photosynthetically active radiation, like they say it does.

I took a hydrofarm par meter, and a lux meter, and modified the lux meter, and got the same exact readings as the hydrofarm meter from several points of measurement of the light.

My current light meter i modified, ( Uni-T ) was used by Migro tests, which he created the conversion factor table for, and was the most consistent with apogee 500. I then converted the difference percentage of the apogee 500 and the apogee 610 EPAR meter, which measures further then the 400-700 range, to measure IR and UV, and made adjustments to my meter, because my lite, the Perfect Sun dwarf Star, has a bunch of IR and UV, and i can tell ya, its pretty dam close if i went head to head with the Apogee610.

Anyways, the whole meaning, its to get close, a generalization of what the PAR COULD be, without dishing out $600

 

[Icemud]

I know that Ice, What i said was, the HYDROFARM PAR meter, is a scam device, that converts LUX, and not photosynthetically active radiation, like they say it does.

I took a hydrofarm par meter, and a lux meter, and modified the lux meter, and got the same exact readings as the hydrofarm meter from several points of measurement of the light.

My current light meter i modified, ( Uni-T ) was used by Migro tests, which he created the conversion factor table for, and was the most consistent with apogee 500. I then converted the difference percentage of the apogee 500 and the apogee 610 EPAR meter, which measures further then the 400-700 range, to measure IR and UV, and made adjustments to my meter, because my lite, the Perfect Sun dwarf Star, has a bunch of IR and UV, and i can tell ya, its pretty dam close if i went head to head with the Apogee610.

Anyways, the whole meaning, its to get close, a generalization of what the PAR COULD be, without dishing out $600

My bad.. I misunderstood what you were getting at... LOL. I agree with you on the hydrofarm "par" meter for sure.



I've seen a few "reefer" (salt water tank enthusiasts) forums that have also done similar as you have and converted them to work accordingly. Thats pretty rad that you DIY'ed it and got compatible results to the Apogee 500. There was a forum post (cant name the forum here) but it was a really good breakdown and build of similar to what you did with a ton of info... wish I could post it here but its competition to this forum.

I thought about buying a spectrometer when I was doing all of the sponsored light tests and such but just couldn't justify spending a few grand on a measurement tool I wouldn't really use much. Its definitely about getting a good idea of what PAR of a light could be, and what tool works the best is really up to the grower. (although these LED companies really should step it up on educating their customers and supplying them with data). lol.

Sorry for the confusion brother! I haven't smoked yet today which is probably why I misunderstood you.. LOL.

 

[Mayne]

No worries IceMud, thats why i clarified it a bit more. I didnt take it like, " WTF you TALKING ABOUT". I follow you, i know your demeanor Bro..

I do know axactly what forum your referring to, spent alot of time there tryn to figure it out myself, and whats funny is, when the thread finally came to a close, after filter color, mix match filter combinations, and hours of fiddling around, the OP came to the conclusion, just converting lux is the best avenue to take, LOL>.

with that said, 99.9% of growers, Wont ever buy a $600 meter to grow some tent fruits, but this will get them pretty dam close to knowing what kind of light levels they are reaching. Even it ifs for shits and giggles, its a good tool to have in the grow box. The light i use, is strong as heck, and not knowing the power of photons it throws out, can be detrimental. Heck, even for electric cost purposes alone, with newer light tech now, no need to hammer the 3 week old plants with 600 watts. My current grow, is using about 100 watts, in a 3x3 while still using optimal PAR range.

 

[The70’s]

I believe i encounter this when tuning a room using a calibrated mic and a software program to see on my laptop what my ears cannot.
I use my software because in time i know what sounds good, and as long as my ears enjoy the sound, what my eyes are seeing on the screen reinforces what the tune is. People believe a “flat” sound is what sounds best, i have never found “flat” good, i like a nice house curve.

Im looking to get the plants centered under the light, and hit a mid level Lux for each phase of growth, when i find it, i’ll also record the watt draw from the wall.

Im not looking to perfect anything so soon in my growing experience, but all meters have use, its just the weight you give em. I understand whats being offered and thank you all for offering up great advice. So far this has already been an interesting adventure and all your words are important !!

Now the real questions, what music do your plants like !!!!!!

 

[Mayne]

I believe i encounter this when tuning a room using a calibrated mic and a software program to see on my laptop what my ears cannot.
I use my software because in time i know what sounds good, and as long as my ears enjoy the sound, what my eyes are seeing on the screen reinforces what the tune is. People believe a “flat” sound is what sounds best, i have never found “flat” good, i like a nice house curve.

Im looking to get the plants centered under the light, and hit a mid level Lux for each phase of growth, when i find it, i’ll also record the watt draw from the wall.

Im not looking to perfect anything so soon in my growing experience, but all meters have use, its just the weight you give em. I understand whats being offered and thank you all for offering up great advice. So far this has already been an interesting adventure and all your words are important !!

Now the real questions, what music do your plants like !!!!!!

Well, to be honest. I have a hearing problem, where everything is amplified to me. Its called misophonia. But i also have problems with trucks, motorcycles, dogs, bass from car stereos in a distance, trains, pretty much anything that registers very low frequencies. So i have Alexa's alllll over my house that play Thunderstorms. Where my closet is in my office, i have a continous loop of thunderstorm on a mp3 player, hooked to PC desktop speakers, so it sound exacly like a thundrstorm, that blocks out about 80% of outside noise for me. I cant sleep or work without it, so its on 24/7 for yearssssss, lol.. When im awake, i have 1 Alexa that plays 70's all day. So really, they hear Thunder and Rain 24/7, LOL

Misophonia is a condition in which individuals experience intense anger and disgust when they are confronted with sounds made by other human beings1. In particular, sounds like chewing, lip smacking or breathing may cause intense anger and physical arousal2,3

BUT, when i blaze up and chill out, I like Rap, but usually Just Berner. ( creator of GirlScoutCookies and the Cookie Cannabis Brand ) Pink FLoyd, LedZ, Mick, type throwback music.

 

[The70’s]

Well, to be honest. I have a hearing problem, where everything is amplified to me. Its called misophonia. But i also have problems with trucks, motorcycles, dogs, bass from car stereos in a distance, trains, pretty much anything that registers very low frequencies. So i have Alexa's alllll over my house that play Thunderstorms. Where my closet is in my office, i have a continous loop of thunderstorm on a mp3 player, hooked to PC desktop speakers, so it sound exacly like a thundrstorm, that blocks out about 80% of outside noise for me. I cant sleep or work without it, so its on 24/7 for yearssssss, lol.. When im awake, i have 1 Alexa that plays 70's all day. So really, they hear Thunder and Rain 24/7, LOL

Misophonia is a condition in which individuals experience intense anger and disgust when they are confronted with sounds made by other human beings1. In particular, sounds like chewing, lip smacking or breathing may cause intense anger and physical arousal2,3

BUT, when i blaze up and chill out, I like Rap, but usually Just Berner. ( creator of GirlScoutCookies and the Cookie Cannabis Brand ) Pink FLoyd, LedZ, Mick, type throwback music.

Wow, im sorry, but glad you find relief. Im pretty toastie on some cannabutter mixed with peanutbutter and Nutella, and listening to Rush Moving Pictures, ummmm way to loud in a newly assembled Sonos system in my livingroom. Its an Arc with (2) Ones as rears, im definitely getting the matching Sub very very soon…….

 

[TorturedSoul]

Sound might be... somewhat... of a rough analogy to the above concepts. Precise measurement can show which audio component is better - but a person might actually prefer the lesser one because they simply like the way it sounds.

Our eyes, like our ears, are not scientific measuring devices. What we prefer (or have evolved to make more use of) and what the plant uses... differs.

 

[Icemud]

I believe i encounter this when tuning a room using a calibrated mic and a software program to see on my laptop what my ears cannot.
I use my software because in time i know what sounds good, and as long as my ears enjoy the sound, what my eyes are seeing on the screen reinforces what the tune is. People believe a “flat” sound is what sounds best, i have never found “flat” good, i like a nice house curve.

Im looking to get the plants centered under the light, and hit a mid level Lux for each phase of growth, when i find it, i’ll also record the watt draw from the wall.

Im not looking to perfect anything so soon in my growing experience, but all meters have use, its just the weight you give em. I understand whats being offered and thank you all for offering up great advice. So far this has already been an interesting adventure and all your words are important !!

Now the real questions, what music do your plants like !!!!!!

Ahh Room Correction you speak my language lol I found the same thing with "flat" room responses.. just dull and boring although accurate, having a slight curve was always my preference too. A nice slight boost in the bass and treble sections really seemed to get my mixes on point

I would say my plants like all good music... ranging from rock to hiphop to classical and jazz. As long as its good my plants will jam

 

[Icemud]

No worries IceMud, thats why i clarified it a bit more. I didnt take it like, " WTF you TALKING ABOUT". I follow you, i know your demeanor Bro..

I do know axactly what forum your referring to, spent alot of time there tryn to figure it out myself, and whats funny is, when the thread finally came to a close, after filter color, mix match filter combinations, and hours of fiddling around, the OP came to the conclusion, just converting lux is the best avenue to take, LOL>.

with that said, 99.9% of growers, Wont ever buy a $600 meter to grow some tent fruits, but this will get them pretty dam close to knowing what kind of light levels they are reaching. Even it ifs for shits and giggles, its a good tool to have in the grow box. The light i use, is strong as heck, and not knowing the power of photons it throws out, can be detrimental. Heck, even for electric cost purposes alone, with newer light tech now, no need to hammer the 3 week old plants with 600 watts. My current grow, is using about 100 watts, in a 3x3 while still using optimal PAR range.

I hear you with the new lighting tech... about 5 years ago I was at the top end of the lighting with Citizen COBs pushing around 1.7 umol/joule and now most modern lights are almost pushing 3 umol/joule.... I think I need to upgrade soon too... I do love COBs though but really would be nice to get some of those new Samsung diode arrays they are putting out.

I think right now my veg tent (3x5) is around 200w and my flower tent is around 350w total... HUGE difference from the HID days with a 400w MH and 600w HPS in the same tent for flowering..

Really sorry to hear about your Misophonia in hearing... that has got to be awful. Great idea with the thunderstorms. If ya ever wanted to try some white noise, let me know and I could filter it according to your hearing thesholds lowering the bass end and boosting mid and high range if you thought it would help.

 

[Roy Growin]

50w per sq/ft works fine
Then it's all about spectrum

 

[Mayne]

I hear you with the new lighting tech... about 5 years ago I was at the top end of the lighting with Citizen COBs pushing around 1.7 umol/joule and now most modern lights are almost pushing 3 umol/joule.... I think I need to upgrade soon too... I do love COBs though but really would be nice to get some of those new Samsung diode arrays they are putting out.

I think right now my veg tent (3x5) is around 200w and my flower tent is around 350w total... HUGE difference from the HID days with a 400w MH and 600w HPS in the same tent for flowering..

Really sorry to hear about your Misophonia in hearing... that has got to be awful. Great idea with the thunderstorms. If ya ever wanted to try some white noise, let me know and I could filter it according to your hearing thesholds lowering the bass end and boosting mid and high range if you thought it would help.

THANKS BROTHER. I will keep that in mind for sure.

If you ever plan to upgrade, dont skimp on PerfectSun LED, I will never use another light myself. I think Neil revolutionized the LED industry early on personally. Pretty sure he was the first to put lenses on smd chip LEDs. But his lights are no joke. You see the monster he has going now, unreal..

The dwarf Star that Im using now, is only 240 watts, and last grow, i didnt even use more then 200watts in flower, didnt need to. Not plugging PerfectSun, just its a bad ass light, lol.. Gives a 600watt HPS a run for its money.


I still have a Photon Phantom from Wayyyyy back when Board lights first became mainstream.. I actually won it, and was the last we seen of dude. I even have a GrowPro HM660Pro that is still in the box, that i probably will never use, lol..

A12-12--day36-wed5.png

• Mayne
• Apr 25, 2018

 

[Mayne]

Wow, im sorry, but glad you find relief. Im pretty toastie on some cannabutter mixed with peanutbutter and Nutella, and listening to Rush Moving Pictures, ummmm way to loud in a newly assembled Sonos system in my livingroom. Its an Arc with (2) Ones as rears, im definitely getting the matching Sub very very soon…….

ahh thanks Bro.. I used to be into the stereo thing, never a house sterio tho, ( oddly ) more car audio. Pretty much cause i dont want to raise hell in my neighborhood, then other people think they can do it too , LOL..

 

[Delps8]

"Watts vs PPFD - which one do you use?"

BUT, a photon flux, is still a measurement of intensity. And Lux reads as intensity. I personally think the PAR meter is the biggest Grower gimic in the industry. Especially after i bought a hydro farm PAR meter, and tested out lights that i knew for a fact, via utub videos of measurements, as a guild.

So, at the end of the day, its exactly a lux meter, but it just converts the readings into a "PAR" measurement, and charge 500% more.

So i configured a meter, thats gives a better "BallPark" figure then hydrofarms PAR meter, and just marking it up 110%,

Per the attached graphic, lux meters read a completely different part of the EM spectrum than a PAR meter. And a PAR meters read a different part of the EM spectrum than does an ePAR meter.

Interesting that you bought a Hydrofarms PAR meter. When I was started out trying to find a way to measure light, the Hydrofarm was off the market but the Ambio-something was there, and there was something else floating around on Amazon. They use the same OEM unit and just badge it.

I think Hydrofarms is a PAR meter. IIRC, they do state that and they're in the price range of the other low end PAR meters that use the same cheap guts.

Regardless, I wouldn't buy any of those products. If you can't swing an Apogee or a LiCor, the SpotOn might be the product for you. OTOH, a lot of weed has been grown by just following the manufacturers recommendations.

More…

When it comes to reading light levels for growing cannabis, I really think that you get what you pay for. When I started growing again (one grow in 2017, resumed in early 2021), the cheap meters were available sometimes but it was either a an Apogee or a LiCor or Photone. I tested Photone, called Corona at the time, and it the accuracy was off. The clones on Amazon are different products designed for a different market than an Apogee (or a LiCor) and that's why they have a different price. The clones are a commodity - they're ½ the price, they can't be recalibrated at the factory, they have minimal support, and the quality of the construction is significantly lower than an Apogee. And they're ½ the price. No surprise.

The cheapest PAR meter I would buy today is the Spot On. It's more than the clones and less than the Apogee. It has a wand attachment and that's a great feature. The Apogee has a detachable, waterproof sensor, and the read out unit is tiny. I haven't used a SpotOn but I think it's a good value. I like the Apogee and I think it's a good value, as well. How can that be? The sensor is waterproof and it separate from the readout unit. If I want, I can send the data to a computer wirelessly. That flexibility costs. If you don't need those features, the Spot On is probably a better choice.

 

[Delps8]

My bad.. I misunderstood what you were getting at... LOL. I agree with you on the hydrofarm "par" meter for sure.



I've seen a few "reefer" (salt water tank enthusiasts) forums that have also done similar as you have and converted them to work accordingly. Thats pretty rad that you DIY'ed it and got compatible results to the Apogee 500. There was a forum post (cant name the forum here) but it was a really good breakdown and build of similar to what you did with a ton of info... wish I could post it here but its competition to this forum.

I thought about buying a spectrometer when I was doing all of the sponsored light tests and such but just couldn't justify spending a few grand on a measurement tool I wouldn't really use much. Its definitely about getting a good idea of what PAR of a light could be, and what tool works the best is really up to the grower. (although these LED companies really should step it up on educating their customers and supplying them with data). lol.

Sorry for the confusion brother! I haven't smoked yet today which is probably why I misunderstood you.. LOL.

The PulsePro has a photospectrometer in it. I have the PulseOne. It reads temperature and RH and calculates VPD. I rely on it completely to help me control RH and temperature to maintain VPD. The Pro adds CO2 and spectrum analysis but it's not cheap at $500.

 

[Mayne]

"Watts vs PPFD - which one do you use?"

Per the attached graphic, lux meters read a completely different part of the EM spectrum than a PAR meter. And a PAR meters read a different part of the EM spectrum than does an ePAR meter.

Interesting that you bought a Hydrofarms PAR meter. When I was started out trying to find a way to measure light, the Hydrofarm was off the market but the Ambio-something was there, and there was something else floating around on Amazon. They use the same OEM unit and just badge it.

I think Hydrofarms is a PAR meter. IIRC, they do state that and they're in the price range of the other low end PAR meters that use the same cheap guts.

Regardless, I wouldn't buy any of those products. If you can't swing an Apogee or a LiCor, the SpotOn might be the product for you. OTOH, a lot of weed has been grown by just following the manufacturers recommendations.

More…

When it comes to reading light levels for growing cannabis, I really think that you get what you pay for. When I started growing again (one grow in 2017, resumed in early 2021), the cheap meters were available sometimes but it was either a an Apogee or a LiCor or Photone. I tested Photone, called Corona at the time, and it the accuracy was off. The clones on Amazon are different products designed for a different market than an Apogee (or a LiCor) and that's why they have a different price. The clones are a commodity - they're ½ the price, they can't be recalibrated at the factory, they have minimal support, and the quality of the construction is significantly lower than an Apogee. And they're ½ the price. No surprise.

The cheapest PAR meter I would buy today is the Spot On. It's more than the clones and less than the Apogee. It has a wand attachment and that's a great feature. The Apogee has a detachable, waterproof sensor, and the read out unit is tiny. I haven't used a SpotOn but I think it's a good value. I like the Apogee and I think it's a good value, as well. How can that be? The sensor is waterproof and it separate from the readout unit. If I want, I can send the data to a computer wirelessly. That flexibility costs. If you don't need those features, the Spot On is probably a better choice.

no doubt. Ive seen the SpotOn, i might get 1 if i ever have, "FU Money", LOL.. But if i did, i would probably spend if on a true, legit PAR meter, that also measures spectrum and all that stuff. seen apogee has a DLI meter to, which is cool, its a PAR meter that crushes the data to give you the DLI, im sure you heard of it.

BUT, im willing to bet, my meter would be within 5% of anything it goes against, LOL.. Good enough for my needs. Heck, i remember i made a spectrometer out of a cereal box and a CD, LOL..

dwcjune4-1

• Mayne
• Jun 4, 2017

 

[Delps8]

no doubt. Ive seen the SpotOn, i might get 1 if i ever have, "FU Money", LOL.. But if i did, i would probably spend if on a true, legit PAR meter, that also measures spectrum and all that stuff.

BUT, im willing to bet, my meter would be within 5% of anything it goes against, LOL.. Good enough for my needs. Heck, i remember i made a spectrometer out of a cereal box and a CD, LOL..

dwcjune4-1

• Mayne
• Jun 4, 2017

A PAR meter does not measure the spectrum of the light source. Just like the name says, it measures "photosynthetically active radiation". That's 400 to 700 nm. ePar, extended PAR, reads from 400 to 750, the higher levels being "far red".

Why the need for a spectrometer? Concern about spectrum shifts as your lights age? That's "worm level" in the weeds!