PAR measurement thread

[zoiz]

PPFD is photons per area per second. So the measurement obviously changes according to distance. 5cm away you might catch all the photons, 10cm away, you'll catch 1/4 as many photons, etc, etc. because of the inverse square power law.

So what distance are people supposed to measure their PPFD from? Is there a standard distance? It's very confusing to me when PPFD measurements are given without a distance.

 

[MeGaKiLlErMaN]

PPFD is photons per area per second. So the measurement obviously changes according to distance. 5cm away you might catch all the photons, 10cm away, you'll catch 1/4 as many photons, etc, etc. because of the inverse square power law.

So what distance are people supposed to measure their PPFD from? Is there a standard distance? It's very confusing to me when PPFD measurements are given without a distance.

Thats why you give the distance.

 

[cdgmoney250]

It's very confusing to me when PPFD measurements are given without a distance.

That's because those are arbitrary and irrelevent numbers being posted. Lot's of people have even been estimating their PPFD based off of efficiency spreadsheets and individual chip tests, regardless if their "build/grow" is totally different.

There is no standard distance measurement as many lights/fixtures are quite different and will range in output. We should really be looking for target PPFD numbers for a set area, and build the fixture (or buy the fixture) that will reach those target light levels. Distance from canopy to reach those target numbers can vary widely depending on the fixture.

 

[MeGaKiLlErMaN]

That's because those are arbitrary and irrelevent numbers being posted. Lot's of people have even been estimating their PPFD based off of efficiency spreadsheets and individual chip tests, regardless if their "build/grow" is totally different.

There is no standard distance measurement as many lights/fixtures are quite different and will range in output. We should really be looking for target PPFD numbers for a set area, and build the fixture (or buy the fixture) that will reach those target light levels. Distance from canopy to reach those target numbers can vary widely depending on the fixture.

Yes, thats what Im getting at, but also bringing in wattage to the equation. If you can get 1000PPFD in a 4x4 (at any height) for less watts then youre making some serious ROI. Thats the premise Im going for.

 

[PhotonFUD]

Yes, thats what Im getting at, but also bringing in wattage to the equation. If you can get 1000PPFD in a 4x4 (at any height) for less watts then youre making some serious ROI. Thats the premise Im going for.

I will take an average of ~410 umoles to 80% or more of leaf surface over 1000 hitting the top 20%.

The answer you seek is provide light to all sides of the plant.

 

[Greengenes707]

I will take an average of ~410 umoles to 80% or more of leaf surface over 1000 hitting the top 20%.

The answer you seek is provide light to all sides of the plant.

How do you even know the difference. You haven't ever used either.

 

[PhotonFUD]

How do you even know the difference. You haven't ever used either.

Well that is easy. I have this device that measures PAR, well more specifically, PPFD. It tells what light the plants are getting at the leaf which seems to always be either more or less than 1000ppfd.

I understand that you are really proud of your '12 year grower' and 'long time member of RIU' self proclamations but your foray with a little indoor garden doesn't make you an expert in horticulture. You are still a hobbyist.

And there is nothing wrong with that. Hobbies are where professionals and amateurs of various different backgrounds can contribute information and share experiences. Just like religion, you are free to believe in what you want and if it works for you, great!

But please don't denigrate those who are interested in the science to help improve their results. There is a lot of great research going on right now both public and private funded that can be of benefit.

 

[sixstring2112]

my meter should be here i a few hours

 

[Greengenes707]

Well that is easy. I have this device that measures PAR, well more specifically, PPFD. It tells what light the plants are getting at the leaf which seems to always be either more or less than 1000ppfd.

I understand that you are really proud of your '12 year grower' and 'long time member of RIU' self proclamations but your foray with a little indoor garden doesn't make you an expert in horticulture. You are still a hobbyist.

And there is nothing wrong with that. Hobbies are where professionals and amateurs of various different backgrounds can contribute information and share experiences. Just like religion, you are free to believe in what you want and if it works for you, great!

But please don't denigrate those who are interested in the science to help improve their results. There is a lot of great research going on right now both public and private funded that can be of benefit.

Would you stop trying to deflect to your personal feelings. You have no experience with anything you have said.
You have not used 1000µmols or 400µmols over any plant species or cultivar, let a lone cannabis. You have no idea how either of them work in theory or real world applications.

Please provide some experience and examples of anything you have said.

 

[PSUAGRO.]

my meter should be here i a few hours

Nice , which meter did you end up buying?

 

[sixstring2112]

This hydrofarms meter,and im thinking about using my phone flash to grow some pot.just look at those oooomoles

 

[PSUAGRO.]

This hydrofarms meter,and im thinking about using my phone flash to grow some pot.just look at those oooomoles
View attachment 3787927

Haha......... anyone confirm it can pick up 660nm+?

 

[Yodaweed]

Well that is easy. I have this device that measures PAR, well more specifically, PPFD. It tells what light the plants are getting at the leaf which seems to always be either more or less than 1000ppfd.

I understand that you are really proud of your '12 year grower' and 'long time member of RIU' self proclamations but your foray with a little indoor garden doesn't make you an expert in horticulture. You are still a hobbyist.

And there is nothing wrong with that. Hobbies are where professionals and amateurs of various different backgrounds can contribute information and share experiences. Just like religion, you are free to believe in what you want and if it works for you, great!

But please don't denigrate those who are interested in the science to help improve their results. There is a lot of great research going on right now both public and private funded that can be of benefit.

What scientific information have you ever posted that's not copy/paste? Do you even grow weed?

 

[sixstring2112]

Just took some readings in veg room .all t5 fixtures with very different readings
The hydrofarm fixtures come in last place.badboy fixture was quite a bit brighter.but theres this one fixture i got at home depot.it was cheap as hell to.just a simple 4 x t5 4 ft lamp fixture and it was well over 100 ppfd brighter than the badboy.need to do some bulb swaps and see whats up.i always thought that fucker was bright,and it seems the bulbs last longer in it as well.i cant even remember the last time I change a bulb in it lol

 

[Icemud420]

4 pages of bickering and 1 person posted results... awesome and informative thread...

Budmaster COB-X-4, CitiLED 3500k gen 4 COBs, 200w actual draw. Used an Apogee MQ200. Measured in a 2.5x5'x7' hydrohut tent.

 

[Icemud420]

Budmaster GOD-4 panel. 175W actual draw, osram SSL chips, measured in a 2.5x5x7 grow tent with an apogee Mq200.

 

[Icemud420]

Budmaster GOD 8, PPFD at multiple heights. Osram SSL chips, 358W actual draw, 3.16A. Measured in a 2.5x5x7 grow tent.

 

[PhotonFUD]

Would you stop trying to deflect to your personal feelings. You have no experience with anything you have said.
You have not used 1000µmols or 400µmols over any plant species or cultivar, let a lone cannabis. You have no idea how either of them work in theory or real world applications.

Please provide some experience and examples of anything you have said.

Personal feelings? It appears that you are the one who has the personal issues. Since you can't understand the science, your approach has been to try and bully your opinions as facts as if you were someone of some importance. I like most intelligent people could not care less about what you think or put any value into what you consider social status as validation of your claims.

I do care when you try to come across as some kind of expert when you have absolutely no formal education, training, certification or validation from an accredited educational institution. Reality check, you are no different than any other gardener. Oh, sorry I forgot, you have a failed horticulture lighting business as well so does that make you less or more qualified than an average gardener?

Maybe I should put it another way that you 'kind' might be able to understand better:

"Kid until you get degrees in plant science and physics you are nothing more than some punk growing pot in a basement closet and posting it on youtube"

Anyhow I will continue to point at the science done by real professionals with real qualifications from real educational institutions that do it for real commercial operations that have real money at stake. You can keep playing around with your little garden and act like a Kardashian.

 

[testiclees]

Personal feelings? It appears that you are the one who has the personal issues. Since you can't understand the science, your approach has been to try and bully your opinions as facts as if you were someone of some importance. I like most intelligent people could not care less about what you think or put any value into what you consider social status as validation of your claims.

I do care when you try to come across as some kind of expert when you have absolutely no formal education, training, certification or validation from an accredited educational institution. Reality check, you are no different than any other gardener. Oh, sorry I forgot, you have a failed horticulture lighting business as well so does that make you less or more qualified than an average gardener?

Maybe I should put it another way that you 'kind' might be able to understand better:

"Kid until you get degrees in plant science and physics you are nothing more than some punk growing pot in a basement closet and posting it on youtube"

Anyhow I will continue to point at the science done by real professionals with real qualifications from real educational institutions that do it for real commercial operations that have real money at stake. You can keep playing around with your little garden and act like a Kardashian.

Cringe worthy exposé of your insecurities. Mod, please move this to the medicating section.

 

[MeGaKiLlErMaN]

Budmaster GOD 8, PPFD at multiple heights. Osram SSL chips, 358W actual draw, 3.16A. Measured in a 2.5x5x7 grow tent.

View attachment 3787969 View attachment 3787970 View attachment 3787971 View attachment 3787972 View attachment 3787973

Results are in my signature.