Is PAR really 400-700 nm? The McCree Curve Revisited with evidence ePAR should be the new standard.

Dr. Bruce Bugbee breaks down the latest evidence that the officially recognized PAR (aka PPFD) range of 400-700 nm should be revised to include far-red photons up to 750 nm. The traditional photosynthetically active radiation range was defined based on research by Dr. Keith McCree and other scientists and has been the standard for measuring plant lighting efficacy for over 50 years. Should the new "ePAR" (extended PAR) range become the new standard? Check out the newest evidence and implications presented in this video and judge for yourself.
Learn more about translating PAR measurements to ePAR measurements here: cdn7.bigcommer...
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[@user-bt2lx4gy7h]

I have a picture of Dr Bugbee hanging in my grow room

[@eggspanda2475]

that's not weird

[@HAPPYHERBS1]

In bugbee we trust 🙏

[@drak_darippa]

bro i want to do the same thing. like chairman mao or kin jong un

[@smellydan]

I’ll be nice and just say, GROSS.

[@aficionadoofthefinestherbs4722]

People put pictures of Jesus on their wall and you don’t call it weird nor gross!!?? At least he is paying respect to real person;)

[@leaf5team]

Play -> Pause -> Rewinding -> Play -> Pause -> Rewinding Outstanding information as always = Apogee Thank you very much; Dr. Bruce Bugbee Sea

[@growfluxinc3939]

This is a much needed change - your leadership on this is much appreciated. Chris linked us to a poster that has a table titled "Theoretical and measured ratios of ePAR to PAR." It would be helpful if you could post a video on these numbers so growers can understand how to translate PAR numbers into ePAR numbers

[@PeterKKraus]

Watch some DR MJCOCO growlight reviews. He uses both PAR and ePAR readings.

[@ApogeeInstrumentsInc]

Check out the poster here! cdn7.bigcommerce.com/s-0oei9zu/content/sensor-to-measure-extended-PAR.pdf

[@rono7494]

The enthusiam regarding "Repeat his data", this statement....👌💯! Love the research and data you're able to produce Dr. bugbee!

[@scottmarshall6766]

Very good presentation (as usual) Thanks, Have the Apogee ePAR meter (MQ-610 380-760nm), going to play with supplemental Far red lighting this winter. Us amateur researchers will be testing as well.

[@dutchbanderlindt4227]

Very nice, dopamine for the plants!

[@LosRiji]

What da hehjl Sir

[@The_Blake_Creator]

It's interesting how optics and refraction of light has given us the power to understand the plants world. Not always you hear such scientific approach mixed with Dark Side of the Moon 👍 Great Talk Dr. Bugbee.

[@Jreichh]

smartest man in this field that I know of 🔥

[@joshuabusick1940]

Outstanding information, the work that you guys do is phenomenal and let me speak for everyone when I say thank you

[@TronSAHeroXYZ]

Thanks for all your work Mr. Bugbee.

[@buschdoktor6127]

I smoked a bong evertime he said _Wageningen_ in a clear pronunciation without any distinctive Dutch mumbling and funny emphasis on the last syllable. Now I'm so high that I was able to replace my far red LED with the blank stare of my red eyes to save electricity. Thank you, Dr. Bugbee!

[@Kingramze]

Fascinating. If and when I'm in the market for more grow lights, I will have to try to keep this in mind - or perhaps I won't have to if they update their specs accordingly. This could be huge for indoor hydroponics operations.

[@DegustoDelSol]

Great as always! Thank you!

[@FluffyFerretFarm]

As usual I will need to re-watch this over and over to completely wrap my brain around this.. 😉

[@doktorhunggari4415]

Dr. Bugbee, when testing E-par’s morphological affects, is DLI constant within each spectrum test? Far red morphology seems be affected by intensity of blue LEDs on my fixture.

[@themanguybuddyguy9852]

Thank Mr bugbee highly appreciated this answers so many of my questions

[@tekeraq]

First of all congrats amazing presentation. I did some “amateur” work while testing beta testing fertilizer for hydroponic cultures, that included testing the fertilizers under different light conditions, Concerning the far red spectrum what we observed is that the tolerance of co2 levels increased, brix also higher and the EC dropped considerably faster when far red was used this resulted in bigger yields, we always tought it was the shadow or the "summer light" effect we never considered it was affecting the efficiency of the photosynthesis. About the uv light, we found some exceptions cultures that had measurable increase in crop result ( also in leaf Brix, the only way i had to measure the result of the photosyntheses ) but almost all the plants had changes in leaf design and especially interesting was that it increased the resistance to pests and diseases.

[@mikedavis1137]

Thank you Bruce for your LED classes. I’m old school bulb and WOW led is awesome but you must be careful

[@stephania8784]

Dr. Bugbee for president!

[@1ntwndrboy198]

I appreciate this information in your research I had studied your prior research and highly provided me with information for which I used to buy the correct lighting for low price

[@PeterKKraus]

It is at Dr MJ COCO. It really isn't a huge difference. The PAR versus ePar numbers are in the neighborhood of 50 ppfd difference.. It won't affect the quality of a grow if you don't have ePAR readings.

[@Derssi10]

depends totally on what kind of light you use. if you have fixture that has good far-red diodes, it could be making pretty big difference, not to mention the morphological differences it is doing also. most of todays fixtures have only 660 nm red light, but that is about to change if they catch these researches.

[@jakebrake7054]

They’ve already begun to change. They now have LED grow lights with adjustable far red to 780, was the highest while 730 was the most common. Not quite as well as the 750 but, it is an improvement!

[@PeterKKraus]

@@jakebrake7054 Actually, 660 is most common and some manufacturers add a few 730nm in the mix also. Unfortunately they also use useless UV LED along with the 730.

[@Derssi10]

@@PeterKKraus to say uv led is useless is a bit confusing. uv light emitted from led for sure is quite weak, but not useless in right quantities. it can improve terpene production by making the plant have immune response on that stress. but yeah, right now uv light is way more efficient from other sources than led

[@PeterKKraus]

@@Derssi10 UV LED are useless. They emit a negligible amount of UV radiation. Fluorescent UV tubes or CFL UV are the only options other than sunlight.

[@kellyhill4410]

Wow!! This was very interesting and informative also. Thank you Dr. Bugby. Really do appreciate the time and effort put into these educational , horticulture lighting videos.. 🤜🌟🤛🪴🪴🪴

[@LibertyDIY]

Awesome work and explanation. Thank you once again Bruce!

[@ajthornton835]

Maybe a dumb question, but for ePAR, why is the UV portion excluded? From the graph, it looks like there's reasonable photosynthesis until ~350. Is IR just that much more effective and thus included?

[@ApogeeInstrumentsInc]

Dr. Bugbee addresses this at the 10:30 mark of the video. The photosynthetic efficacy of UV is crop dependent. Radishes, for example, are far more photosynthetically affected by UV then other crops. But for the vast majority of crops, the cutoff is a lot closer to 400, thus the cutoff for developing a general definition (400-750 nm) and developing a tool of measuring ePAR, 400 nm makes the most sense as the cutoff. It would be bad to put a lower cutoff because it only applies to a very small number of crop types. For some crops, Dr. Bugbee recommends a spectroradiometer, not an ePAR sensor for measuring UV.

[@ajthornton835]

@@ApogeeInstrumentsInc thank you so much! this makes total sense. I t didn't put 2 and 2 together that since it only benefits a narrow range of plants, it doesn't need to be included.

[@TheAmericanOne]

Is the deviation of the 6% (18%to12%)due to the filtering of the UV side?

[@Canna_Science_and_Technology]

Just awesome. Thank you so much for sharing.

[@gtalckmin]

Hello Bruce, Given that photons have (by definition) a specific amount of energy and this energy can excite specific electrons, how come a different energy-photon (ePAR) are reacting with photosystems? In other words, does the photosystems change their molecular bond to accommodate for a extended PAR? Cheers, Gustavo

[@Maxalach]

what if UV light is important for quality (terpenes etc.) ?

[@LosRiji]

I'm running an El cheapo 30w 405nm flooder led thingy in there. Plants lovin it. I'm lacking the ability to see the results without it because it's such a new crop but I will not grow without it

[@AMatroskin]

how do you think, if i use led light like main source of light, can i add simple incandescent lamp for far red source, it have enough IR radiation in it's spectrum, isn't it?

[@rosskrt]

I think it would work as a far-red source, but it would be terribly inefficient in terms of energy. Keep us updated on the results!

[@freedom_born]

CFL warm white is better.

[@LosRiji]

Oh wow. What a great time to be born in. Thanks

[@rafavega83]

Gracias profe.

[@jrsgarage3244]

Robin Williams counter space twin 👍😇

[@eggspanda2475]

tx Doc

[@nicedude5556]

My Horizon LED have 710 Watt the light is so strong with 1500 Watt HPS very crazy LED.

[@kenyattagrows4215]

My professor 🧑‍🏫

[@f_youtubecensorshipf_nazis]

I was growing plants under actinic lights (all I had at the time) and was kind of surprised how well they did. They got a little sun from a window but most of the light was actinic from bulbs intended for reef tanks. That experience is why when I started building custom led lights for plants and for aquarists, I always included 390 nm through to 430 nm leds. I think the aquarist research community and the plant growers could get a lot from each other.

[@1ntwndrboy198]

That would absolutely make sense because plants started in the water and water is a natural light filter.

[@express375]

never judge a book by it's cover

[@LosRiji]

Never book a judge undercover

[@j562gee0hdeewestsdegethemuLa]

Buddah bruce

[@kenyattagrows4215]

KIND LED the best.

[@izzem]

I have the X420

[@kenyattagrows4215]

@@izzem so do I. And I love it

[@LosRiji]

Greenception GCx is King

[@redeye1773]

far red a dinosaurs delight larger snacks

[@prestontingley8914]

Par should be VPAR for ‘visible par’ and epar, should be simply par(:

[@FreemanVashier]

Can reptile heating lamps that emit uv a and b be used as a supplemental light for crops that benefit from those bandwidths?

[@LarsLarsen77]

Get a T5 UV bulb. They're brighter.

[@FreemanVashier]

@@LarsLarsen77 Thanks, I had grabbed a small reptile light to kill off a small mold spot that had just started to form. That got me thinking about the long term bene's of a cpl hours a day during flower

[@FreemanVashier]

@@LarsLarsen77 any recommendation for distance needed?

[@Albopepper]

Great info & explanation as always! How bout sharing the PDF of the published paper instead of locking it behind a pay wall??? 🤓

[@thecowman6807]

Doesn't the red to far-red ratio have to be incredibly low,

[@rosskrt]

My guess is that, other than shade avoidance response, the increase in lettuce yield is caused by the enhancement of cell expansion, which is an effect of far-red light

[@MO-ch6ni]

Always love the videos Bruce. I think him and green genes should do a video together

[@Санчес-я1т]

Thank you very much! Very nice! Perfect! Wonderful! Excellent! Great! Amazing!

[@R3cKi7]

oh what I would do for one of those ePAR DLI portable units! Thank you Bruce, for all you do for the world! ❤️ from West Australia

[@monaimlouriga6603]

Thank you apogee 🙏♥️☺️

[@izzem]

As always, appreciate your time and work

[@Skrekozila]

Could Dr. Bugbee tell about optimal concentration of potassium for cannabis?

[@Slaveman00799]

The twin tower diagram allowed me to visualize the impact of the Far-Red photons. I appreciate the free content you release on KZbin. I would love to attend one of your lectures

[@EAster33]

bugbee-when i say "we" i mean others too. hahaha mans wants to include everyone so he letting you know!!

[@mi.terpology]

Leading scientific exploration of cannabis bugbee 🐐🐐

[@nate6748]

the Marshall lettuce example at 10:20 is super interesting! would it be accurate to equate that to the anecdotal "green is more potent than purple" because green cultivars use UV photons better?

[@dollartreegrower3969]

light is food!

[@tmalonso]

Plant evolution: “when the far reds show up, winter is coming…better hurry up”

[@rocketboy352]

rad

[@seventeen9718]

Thank you Bruce. Your knowledge is invaluable and you've really peaked my interest with your videos and truly got me interested in the specifics of plant-science/horticulture! Absolute living legend.

[@Runboy7426]

@Apogee Instruments Inc. - do you see these latest findings having any effect on the "Efficiency" ratings of High Pressure Sodium Lamps?

[@jwgrower81]

Yes sir 💯

[@surferdude-ll2qu]

Thnx Bruce 👍🏻 💪🏽🌱

[@ink-og-neatola-tea-no732]

I would like to see tests on spectrum king led, been using them exclusively for years and their data/info rings similar to what I've heard on this channel. Keep up the great works