In-Depth Look at PAR/Quantum Meters

[@Sect76]

Prof Bugbee is the OG when it comes to plant growth. Thank you.

[@kp1242]

Just got the MQ-500. Partly because how much I've learned from Mrs bugbee. Just wanted to say thanks for the easy to understand knowledge. Plus after seeing how you made a video just because a comment on here... Faith restored in humanity haha I needed that.

[@downwithprohibition7364]

Thanks guys this video was very helpful in showing the differences in the full spectrum meters to non. It seems more people need to know about this. We have found a few light manufacturers that have seriously under rated their lights due to the 660nm deep red leds. You guys may know me a little better from my other channel Aqua Nut. We are getting great use out of our MQ 510. I wish we went with the SQ 520 now that I am using it so much out of the water testing grow lights. My head hurts from all of the calculations I need to make haha.

[@workuntilimoon7930]

Love to watch and learn. Thank you for all you do

[@SmartGrowAutomation]

Excellent video thank you for uploading. I was always. confused with how people use PPF and PPFD interchangeably! Seems like PPF should be constant for a given light source (similar to lumens but calibrated to plants and not human eyes) and PPDF should depend on distance from the meter, reflectors, lenses etc (similar to Lux which is lumens per area). Apogee, you guys are a leader in this industry, be the change we all want and make PPF and PPFD make sense!

[@ApogeeInstrumentsInc]

Thanks for posting this! We'll try to have Dr Bruce Bugbee, the founder of Apogee, make a video explaining this clearly (he's a super busy guy), so stay tuned. In the meantime, here is an answer from John in our tech support group that might help: Though the terms PPF and PPFD are often used interchangeably, they technically refer to two different things. PPF, or Photosynthetic Photon Flux, refers to the total amount of photons in the Photosynthetically Active Radiation range (PAR, roughly 400 to 700 nm) being emitted by a light source. This is often measured in units of µmols of light per second. PPFD, or Photosynthetic Photon Flux Density, refers to the amount of photons in the PAR range that are hitting a given surface. This is often measured in units of µmols of light per square meter per second. Another way to think of it is by imagining a garden hose with a wide-pattern sprayer nozzle attached. The entire amount of water coming out of the hose in liters per minute right at the nozzle is similar to PPF, and the amount of water drops actually hitting a specific square meter of the ground at a distance every second is similar to PPFD. A lot of the water will hit the ground around that particular square meter due to the spread pattern of the spray over the distance. To be meaningful, any PPFD number needs to be accompanied by the distance it was measured from the light source. There is a lot more that goes into it, like spatial averaging, but that is the essential concept. Hope that helps! Again, we'll try to put out a good video on this soon. Thanks!

[@SmartGrowAutomation]

@@ApogeeInstrumentsInc Thanks for the response, I agree with John! My comment was basically saying the same thing (PPF~=Lumen and PPFD~=Lux), and that your company should enforce the correct terminology and *not* use the terms interchangeably. Dr. Bugbee in the video said everyone uses the terms interchangeably so he would be using them interchangeably as well.

[@ApogeeInstrumentsInc]

@@SmartGrowAutomation We just had Bruce Bugbee shoot a video explaining these terms. See what you think. kzbin.info/www/bejne/pZLdlpdsdqypmsU

[@SmartGrowAutomation]

@@ApogeeInstrumentsInc That video is great! Very useful to go back over the history of the terms and how they came to be. I am not looking forward to the confusion the new PFD term will be causing though...

[@beeservicesbhavani4566]

Really it is a good video.It shows in-depth of PAR Meter measurement. Thanks to Apogee

[@henrysaw3091]

What a great explanation!! Now I feel like I am a professor in light physics :).

[@Thryfte]

Really appreciate these videos, thanks for sharing all of this information

[@high-reggaeps4706]

Years of knowlegde learned in 1 free seminar

[@icemud12]

Good video, and really like the response curve on the new MQ500!

[@idrissahamad8615]

Thank you so much for clarification, was useful indeed. I got MQ-500. If you got a chance, could you prepare a video on measurement and interpretation of these especially for marine vegetation like seagrasses as Kd? Thanks so much.

[@ThePotGeeki]

Adam Dunn Has invited Dr. Bugbee and me to compare and contrast conventional photobiology and Quantum aka Teslan photobiology on his show May 5.. I REALLY hope the Professor accepts. Dr. Bugbee will represent conventional and I will speak for/about Quantum photobiology.

[@kencaruso4037]

Thank you sir, I get it now.

[@brendawilliams8062]

You have excellent art.

[@YAHYEL-ANUNNAKI]

Thank You!

[@sichingchow3297]

Professor, can you explain what and how PPF(D) will change when the distance changes? Because usually when the LED lights get closer to the plants, the more intense PPF(D)will be. Is there formula to calculate this?

[@gokufoster1169]

when the light gets closer theres more photons compact in one area but when u go futher from it the photons are more spread out and takes up more area just less density kinda like when you get closer to the light it gets brighter because there more cancentrated denser amount of photons coming directly from the source they spread out the futher u go from the source and theres less active photons being that ur distancing away from light its a wave of photons and as u get closer the photons are more compact and as u get further they spread out hence the term density it becomes less dense as u pull away ppf and ppfd can be two different concepts

[@forgetfulfunctor2986]

Given a measurement from the full spectrum sensor, can we find a C-module that represents that measurement and try to decompose it into a direct sum of indecomposables to try to reduce errors further?

[@tiptop1681]

By just following his advice, I have grown 420 lbs per m2, just in 5 days.

[@eugeniahobbs41]

Glad I found this. Great science. I would like to suggest repeating McCree, 1972, using LEDs. Make measurements using Apogee Quantum Sensors, really dial-in the radiation measurements. Then analyse several popular COBs; 3K, 4K, 6K, 10K, just for comparison. Carefully investigate colour temperature. Could be a thesis proposal?

[@parthibanm756]

But in high altitude region PAR Meter shows values 1120, how to interpret this

[@ginomu]

Watching some of the recent videos of Professor's talks i find ironic to hear him say "IR doesn't cause photosynthesis".. things have changed since then i guess.. for good!..

[@godzmazterweedz7120]

expert knowledge and I want all your video's

[@franklinrand9228]

I love watching videos by really smart people. I'd love to see him smoke a big blunt and give this lecture!

[@MidwestAquariumServices]

Great video. I have been looking for this information for a few years. We use the original par meter in our saltwater aquarium store. Will we be able to buy the new sensor and install it on the handheld?

[@ApogeeInstrumentsInc]

+John Easterday Hi John, Chris here, from Apogee. Check out www.apogeeinstruments.com/quantum/

[@zhenhuachen6611]

HOW GREAT YOU ARE, UTU PRO.

[@gtalckmin]

Hey Bruce, congratz! Good work on working on creating a cheap white reference with barium sulfate! Cheers!

[@ApogeeInstrumentsInc]

Hi, gtalckmin! Thanks for the comment. If you're the same person that is heavily involved with using UAVs in agriculture, you should check out our new lightweight field spectroradiometer. It's great for making reflectance measurements over crop canopies. www.apogeeinstruments.com/field-spectroradiometers/

[@gtalckmin]

Congratulations once again! I am really impressed. Have you given any thoughts on working on a imaging sensor? That would enable larger audiences (ie, farmers) to use mapping cloud services . A few band sensor coupled with a pyranometer would great. For UAV + point-measurement spectroradiometer, it would be interest to also have a fore optics with a narrower FOV, otherwise high mixed signals, Currently you the narrower is 25, right? Cheer and success on your business.

[@ApogeeInstrumentsInc]

Yes, the narrowest FOV is 25 degrees. As far as creating an image sensor, we don't have plans for that, but I will pass along your request. Thanks! -Chris (Marketing Director, Apogee Instruments)

[@gtalckmin]

Hey Chis, Thanks for that - I will be happy to see a wider range of products on the Market. Also, please emphasize the need for a narrower FOV - otherwise, at 100m flight, the sensing footprint would be enormous. Good luck!

[@diehardsandman]

I luv u Man! Really, this is a great explanation! Thank you!

[@ag6522]

My plants won't take more then 500 ppfd in week 4 flower...I have the mq500 par meter..can anyone tell me y this would be happening?

[@PeterKKraus]

Where can I rent one for a few days?

[@goonernumone8444]

Download the light lux meter ( android only this works though) then look on " Migro" page he has taken par readings and lux readings and overlaid them on a chart, its not exact but its close , he used a par meter worth 2k so youll get a rough idea,or you can buy them online but they are not cheap ( well some are but they are about as accurate as this chart)

[@faris94khan28]

Its only for white led... Not for blue and red led... Which is not accurate...u still need this quantom sensor.. i watched about the migro video about android app and he use only on white led ... Not the red and blue..

[@kingerror]

Thank you Mr. White.

[@davidlovell7724]

thanks can you give me the best reading for a 600w viparspectre LED grow light as I am about to buy a par meter (NOVICE) as I am new to measuring light, thank you

[@ApogeeInstrumentsInc]

Hi David. Our 500 series quantum sensors will work great for that light. See www.apogeeinstruments.com/full-spectrum-quantum-sensor/ . If you have any further questions we'd be happy to answer them. Please email [e-mail] and someone will respond asap. Thanks!

[@bvolt70]

UV affects plant morphology but not necessarily biomass growth.

[@Brotha00]

So the phone apps aren’t reliable tools?

[@Ze0th]

Now it's 400-750 nm? What changed?

[@ApogeeInstrumentsInc]

Check out this video: Is PAR really 400-700 nm? The McCree Curve Revisited with evidence ePAR should be the new standard. kzbin.info/www/bejne/pGTTc4Clbr6NZ7s

[@Ze0th]

@@ApogeeInstrumentsInc Thanks, I just ordered the mq610.

[@burtonfreeman5205]

Why is UV ignored, isn't UV used in photosynthesis and necessary for certain proteins? Are photons in different wavelengths really equivalent? Why then is there so much hype with red and blue LEDs?

[@ApogeeInstrumentsInc]

+Burton Freeman Thanks for your questions. As it turns out, wavelengths shorter than 400 nm typically do not reach the chloroplasts in leaves because they are filtered out by UV blocking pigments on the leaf surface. UV radiation is thus not included in the definition of photosynthetically active radiation. Although UV radiation has a minimal effect on photosynthesis, it is highly effective in causing the synthesis of pigments in leaves. For example, red lettuce leaves do not turn red unless they are exposed to some UV radiation. For this reason, Apogee instruments offers a sensor calibrated to measure UV radiation. Most people think UV radiation is bad for plants. Our research indicates that some UV radiation is good for plants, just as it is for people. Not all photons are exactly equivalent, but they are close to equivalent. A scientist named Keith McCree published a comprehensive study in the early 1970’s that showed that for leaves in low light, red photons were about 20% more effective than blue or green photons. More recent studies in whole plants in higher light, however, now indicate that the differences among the colors of light are less than what was found in single leaves in low light. So the colors of light (photons of different wavelengths) are nearly equivalent. Recent textbooks in Plant Physiology have good discussions of pigments in leaves (other than chlorophyll) and the effect of the colors of light on photosynthesis. Red and blue LEDs are widely used in LED fixtures because they are more electrically efficient than white LEDs. Some people think that because these colors are effectively absorbed by chlorophyll, they should be more effective in photosynthesis. We now know that white light is equally effective in photosynthesis as red and blue light. Bruce Bugbee

[@zhenhuachen6611]

sensor is the key

[@bvolt70]

Also, setting aside photosynthesis - different wavelengths of light affect the plant's other systems, leaf-and-stem elongation, internodal distance, etc.

[@FinehomesofNewHampshire]

Apogee Instruments Inc. Great video. Thank you.

[@TRUSTME183]

I have one question Will LEDs finish the flowering stage in cannabis?

[@rabaduej]

Wht about age old experiments that show that plants have 2 photosensitive parts to its photosynthesis. Where the first part wants the spectrum of PAR but the secondary process wants IR light. Meaning IR light on its own has no effect on photosynthesis. However when first giving the plant its precious PAR then at the same time introduce the IR spec at the same time there is nearly 2x more photosynthesis.. So shouldnt this effect be factored into to our sensors?

[@ApogeeInstrumentsInc]

Excellent point. You are referencing the Emerson effect, and this effect is currently ongoing research for Bruce Bugbee. Dr. Bugbee recently made a video explaining this so be sure to check it out if you're interested in learning more (kzbin.info/www/bejne/nXmye4SjjquKZ6M). We are also currently developing a PAR-FAR sensor that measures both commonly defined PAR from 400-700 nm as well as IR light (www.apogeeinstruments.com/par-far-sensors/).

[@bungle555]

QXYGEN

[@WS-qy3cd]

lol how nervous is he! :0

[@darrenfenton9280]

Your out if breath because your fermenting not digesting food. My opinion. Hope you read this.

[@vintageboy8730]

i can no help but make this comment the science of the study of light is amazing but God created light to work with the earth nothing will ever compare :)