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PAR Light Quality LEDs & HID: Plant Grow Light Basics -101 (pt 1)


Hi, I’m Al Gracian from albopepper.com. Today’s grow light market is advancing faster
than ever before, especially in the field of LEDs. New models hit the market every month. Lights become more efficient AND more affordable. But the selection process is becoming more
complex as well. We must filter out over-inflated product claims. Meanwhile, we’re trying to understand the
various product specs and what these mean for us. What is PAR light? Do plants benefit from full spectrum light
or is red & blue all that they use? We’ll answer this in this 1st video of a multi-part
series. And then later, we’ll get into PPF, PPFD and
light efficiency. And finally we’ll compare the pros and cons
of various light technologies and their form factors. When looking at the characteristics of a light
source, we can focus on two crucial aspects: First, there is Light Intensity which refers
to how bright a light is. This relates to the photon density. (More on this in the next video.) Secondly, there’s Light Quality which is also important. This refers to the composition of light. How much red is emitted in relation to blues,
greens or any other color? And that’s what we’re discussing today. So lets start with the basics! Grow lights emit radiation within the visible
light spectrum. This chart, which you’ll see time and again,
portrays a narrow portion of the electromagnetic spectrum. Each color has its own unique wavelength,
from violet to red. A specific color can be described by its wavelength
in nanometers (nm). So a blue light may be 450 nm while green
is 550 and red is 680. Travelling left on this graph, towards blue,
each photon (or particle of light) has more and more energy. Moving right, towards red, each light wave
possesses less energy. As you get right outside of the visible spectrum
(below 400 nm) you have Ultra-violet light. Some grow lights may produce UV in addition
to visible light. And interestingly, plants have shown physiological
responses to UV with improved disease and pest resistance. Between 710 and 850nm we have Far-red light,
which plants are sensitive to as well. Far-red does less to drive photosynthesis,
but can greatly effect plant development or morphology. For example, certain ratios of red to far-red
can tell plants that they’re under a canopy of taller plants, triggering them to grow
taller in response. Of course, the most crucial range for plant
growth is within the 400 to 700nm color range. Photons within this range are most effective
at driving photosynthesis. This is referred to as PAR light (Photosynthetically
Active Radiation). Note that this range includes even green light. Wait a second! Don’t many growers emphasize blue and red
frequencies, saying plants don’t use green light? They may refer to green as being completely
wasted light. Well, for decades researchers have demonstrated
that green light serves a useful function and is capable of driving photosynthesis. In fact recent research is revealing some
unexpected benefits of green light, even helping with organic pest control! The point is, don’t prescribe to the oversimplified
mentality that plants only need one or two colors to thrive. They may live and grow, but that doesn’t mean
that all other light frequencies are useless and unneeded. But where did this misconception come from? Well one thing that doesn’t help is the
misapplication of the photosynthesis absorption spectra. People love bringing up this little graph
which certainly makes green light APPEAR useless. Even laying on that popular carotenoid graph
still leaves a big gap. But how was this data gathered? This is based on testing of thin algal solutions. Higher plants (you know the stuff that we’re
trying to grow) do not respond to and process light in the same fashion. They have much more complex structures. In reality, “green leaves of land plants
absorb a substantial fraction of green light.” And this light then drives photosynthesis
as well. So yes, plant leaves reflect SOME green light. And that’s why they’re green. That’s good because this results in improved
canopy penetration. But ultimately, much of that light is able
to be harnessed. Should that really surprise us though? Afterall, the PAR measurements used by horticulturists
give green photons the same weight as blues and reds. So really a broad, full spectrum light source
is a good thing. – not a bad thing. A spectrometer can analyze a light source
revealing the ratios of one color compared to another. Many light manufacturers will share spectral
graphs of their light. It may be portrayed as a curve like this or
perhaps this. Plants respond differently to different combinations
or ratios of light. At different phases of growth, certain spectrum
profiles may enhance results. Professional growers may switch bulbs as their
plants mature and enter their fruiting or reproductive phase. High Pressure Sodium lights are heavier in
the yellow through red end of the spectrum. Meanwhile, Metal Halide lamps emit a larger
amount of blue and UV. You may be familiar with the Kelvin rating
system which is commonly used to describe the color characteristic of Fluorescent lights. Lower numbers like 2100 K have a warm amber
hue while “cooler bulbs” like 6500 K are higher in blue light. With the widespread adoption of LEDs, we do
see LEDs that use a Kelvin rating – but many plant grow lights do not. Instead, they may contain multiple diodes,
each of which emits a unique narrow band of color. A 3 band LED, for example, may contain 1 type
of blue and 2 types of red. Thus, custom tuning of that “perfect” ratio
is often sought ought as one LED seller tries to stand out from the rest. LED Grow lights are showing more and more
color bands. Some even claim to be “full spectrum”. This can be achieved by including a few diodes
that have a phosphor coating. The coating changes the energy state of photons
from a blue diode. The result is a mixture of wavelengths that
produce white light. The reliance on phosphor coatings slightly
reduces an LED’s efficiency rating. But it creates a more rounded spectrum that
is likely to support a broad range of plant types. Light Quality can have a drastic impact on
plant development, effecting the shape and length of plant leaves. But just as important is the overall Light
Intensity. What’s the best way to measure light intensity
when it comes to plants? Our next video will answer that question! Thanks for watching. Please subscribe if you haven’t already. And as always, Happy Gardening!

100 Comments

  1. Al Author

    Thanks man, very clean, educational and right to the point video! Energy to nature is like currency to men. It would be silly to imagine that someone would get rid of $20 bills, but keep the rest. The same analogy goes for plants, nature doesn't waste anything. I'm very lucky that I found your channel! I'll be waiting for your next video.

    Reply
  2. khalid Alamoodi Author

    really amazing, and as always, there are plenty of things learned. Thank you for putting all of this information together. Looking forward to watch the remaining videos in this series.

    Reply
  3. DoctorRetina Author

    wow
    that's amazing info!
    you have a sub 😉
    so we should be using a lot more full spectrum LEDs that means!
    I think I might purchase some of these single watt LEDs and solder them together with your blessing:
    https://m.aliexpress.com/s/item/32748984587.html?spm=a2g0n.search-cache.0.0.7f25570fxeaS2F#autostay

    Reply
  4. FOR8YESHUA Author

    AlboPepper I am glad to be a subscriber.
    A very informative video on the need for full spectrum lighting. I look forward to your updates.

    Reply
  5. cjtmusic2 Author

    Hi! What kind of plant light bulbs would you suggest for Begonia rex plants? I want bigger leaves and but not out of control growth. I will use 1-3 light fixtures in a small bedroom and want the lights to shine on several plants at once. I am growing my plants in soil, not hydroponically. I haven't chosen a fertilizer yet. I will grow other houseplants as well and maybe herbs.What do you think I should buy for the light bulbs? TIA!

    Reply
  6. Heng Heng Author

    Thank-you for the explanation, I'm trying IKEA grow lights for indoor fishes like Koi and Arowana to simulate the Sun for any effects on the fishes colour and growth.

    Reply
  7. Mack Plymale Author

    Albopepper,

    I enjoy your videos. Being that green light in plant growth has been overlooked up until now, I was wondering if you could do a stats. You have two plants. You give both of them the same small amount of blue and red light. Give one plant a little green light and one massive amounts of green. It would be interesting to see how green light effects groth.

    Reply
  8. kemGkem Author

    Lots of good info, Q though how or why make vid like this with this much good info with out talking about the Cob(chip on bord) Led's that surpass all the leds that came before them.
    With the new Cob leds we are finaly getting CRI light scores of 95% and up. copied from there site (Yuji LED’s 400H series high CRI COB provides high CRI, high luminous flux solution. Providing 95 CRI (typical) at up to 6800 lm) check em out there the best i could find online for now.

    Reply
  9. Tom Tiger Author

    Best app for smartphone in combination with professional spectrometer you can find here: http://spectrophotometer.eu/smart-spectrometer-app-for-ios-android/agricultural-lighting-spectrometer-app-ios-android/
    It provides best opportunities for all kind of PPFD-measurements.

    Reply
  10. Crystal Rollins Author

    This video combined a lot of info I've been gathering myself about light spectrums. THANK YOU! Any idea when the 102 (second lesson) video will be coming out?

    Reply
  11. Nicholas Pontus Author

    Having watched a ton of video trying to understand what grow lights to buy, this video is amazing! It's so informative–thank you! I cannot wait for video 2. Just because your videos are so informative, I subbed. Keep up the good work!

    Reply
  12. Forrest Pugh Author

    I just replicated your red/blue LED experiment with my daughter for her science fair project – we changed a few things, such as allowing the plant of choice (raddish in our case) to sprout under the light as well. We found that while the red and blue spectrums DO have a huge impact on growth, without the middle yellow/green spectrum the plants grew abnormally… very quickly, and under developed – it took plants under the blue light twice as long to develop secondary foliage, while those under red-only light never did. Our control group under full spectrum light developed normally, though grew slower and shorter than the red and blue groups.

    Thanks for the inspiration on this!

    Reply
  13. Trever Bull Author

    Hey if you go to horticultural lighting group buy a 2pcs 288-5000k and a doouble heatsink, (1) HLG-150H-54B, a dimmer control you can have a led light that can go from 20-150w watts for about $300 to build yourself. Doing this will get you 3.02 – 2.75 μmoles/joule getting light at 380-780nm. If you want a little more red go with 4000k

    Reply
  14. Cosmic Pangolin Author

    Thanks for sharing that info on the chlorophyll chart being created after tests with algae. That mist be why people are switching over from cfl to those 'blurple' led bulbs and having so much success growing macroalgae in their saltwater tank refugiums.

    Reply
  15. D&L N Author

    I read a paper one time that was written by a Canadian University that proved that there is no such thing as a "full spectrum" light bulb. It's a marketing strategy. I like when you said a "more rounded spectrum" because I think that is what it is.

    Reply
  16. Forted Exe Author

    Hi, Iam looking for the led or t5 that have the shape of tube (for the led), and good of grow fruit, like strawbery or tomato, can you suggest me some product ?
    And which spectrum that good for grow fruit ?
    Thank you

    Reply
  17. jia an Author

    Hi. Thanks for your wonderful video. My name is An Jia, come from China. We also have a plant grow light. Dual head 40 LED beads 14 blue and 26 red timing fuction grow lamp.This is a new designed, fan heat function more powerful than white, and beads life longer.Would you like to test and have it ? If you agree, we would like to ship it to you for free. We promise our product with high quality and workmanship strict.

    Reply
  18. KENNETH FRANCIS RODRIGUES - Author

    Very interesting observations on green (reflected) light. We have to understand that plants have evolved to survive in a full spectrum light environment, when we transfer plants to an artifical light we inadvertently alter the transcriptional machinery as a wide range of genes are regulated by green light. The case is different in the case of algae as you have correctly pointed out, algae and seaweeds occupy different depths in a water body and the light spectrum alters with depth. In addition to this, algae contain accessory pigments which absorb one wavelenght of light and convert the energy to a photo utilizable level. Very good video for scientists.

    Reply
  19. Fish R Relaxing Author

    We are now finding in aquatic lighting that green is a very desirable part of the spectrum. With much more measurable par at depth then blue or red.

    Reply
  20. Wayne Author

    I've been researching this subject to grow my peppers indoors. Thank you for this. Seems to put aside hype and misinformation, and at the very least is a good place to start.

    Reply
  21. Jan Carlo Mata Author

    can i ask how much is the minimum amount of light to keep the plant in veg? im living in a country where its 12/12 all year long and the electricity is waaaayyy expensive. thanks guys! Its just that i cant seem to find the answer online any help will be appreciated.

    Reply
  22. Renjith Ravindren Author

    Hi I have 90 cm x45 x 60 (H) planted am confused used with Spectrum grow light can u suggest which one is suitable for me thanks in advance plz verify the link I posted

    Reply
  23. s.j.j. Ormsfang Author

    I have been using my freshwater aquarium grow lights. Figuring if they are good at growing pants under water that is a good start. Turns out most of the light consists of 7k full spectrum beads, with the addition of rgb beads for adjustable additional lighting in more specific spectrums.

    If I could afford it I would add a quality red and blue supplimemtal (not the main light) light with IR and UV added in. Have a cheaper one, but like anything else, to get a better light you have to pay more

    Reply
  24. brontozaur2 Author

    hello. what you think about this LED??? I want replece HPS400
    https://www.ebay.co.uk/itm/VIPARSPECTRA-Reflector-Series-450W-LED-Grow-Light-for-Indoor-Plant-Veg-and-BLOOM/183205669218?_trksid=p2485497.m4902.l9144

    Reply
  25. fusiondew Author

    Can’t green only reflect green? Maybe it takes the hi’s and lo’s of the green waves, but I’m not convinced they actually absorb anything green

    Reply
  26. zumbaladin Author

    very daring, disguised as a plumber (THE plumber) and giving advice about lights and electricity efficiency.
    Seriously, thank you for all the good advices.

    Reply
  27. Busy Bee Leds Author

    Your about 8 years Behind. LOL But good info..
    Lights have not changed Since I set the standard nm/wavelengths in grow lights back in 2009. I Built first grow light in the world with 22nm. Full Spectrum with out white light.
    But yes there are a million of new Factories/resellers in china just reproducing the lights just a handful of us built back in 2009 – 2010.
    Yes You can grow plants with just green light, I said that back in 2011.
    But When your a small company no one want to listen to you! And when your a big company with lots of money to toss around, you pay manufacturers not to sell to your competitors. Thats what happend to me and after all my hard work all my research. "Advanced Led" haha a bunch off stealing assholes The Diamond series was my series, and then I help the factory produce a new light, and again they pd the factory to stop building my lights. Thats was the last straw I gave up..
    So I turned and Focused On Industrial Led Lightning since 2014 rt after I met my girl friend online who was from Shanghai and who taught me about Industrial Led Lighting, But her factory is in Shanghai not Shenzhen. Smart Women. 🙂
    But I might just get back Into the Grow light industry.
    It Still Looks like people need "The Best product for the best price period or we die trying" "Again"
    That is why I started Busy Bee Leds back in 2009, So that normal people could afford a proper grow light for M.M.M.
    Never Pay over a dollar a watt for a grow light or Industrial Led Light if you do your just paying for their adverting and their new home in the Bahamas.
    Hope this helps some people know that no light priced at 1200$ or even $800 is worth it.. Trust Me it is a rip off.. But I wont name the USA companies. I am sure you can figure them out. After you start searching.

    So tell me do you know what Dual wavelengths are? Doubt it.
    That is why I built lights with 22 different nm in 2009, I included dual wavelengths.
    Well go and search and read about Dual wavelengths if you can find the info.. God Speed.

    Reply
  28. OMEGA473 Author

    Question for all of you. I got some light off amazon and was wondering if it’s dangerous on the ole eyeballs. It’s wave lengths are 660 nm and 460 nm.. it’s also made in China sooooo…. who knows

    Reply
  29. NodNerb Author

    I wish I had found your videos before watching/reading hundreds of videos and articles pushing the old red and blue only narrative. Thanks a tonne, I'm a beginner and this made things make way more sense.

    Reply
  30. Stephen H Author

    I'm a fan of led light strips around the house. If I used a 5630 bright white, and a full blue, and say a 4-1 red/blue together, do you think it might be sufficient? LED strips are cheap and I'm literally looking for the cheapest option.

    Reply
  31. Kalvin One Author

    in 1 word : all led lights with full spectrum for corals tanks will be ok for growing tomatoes from seed to harvest… as corals in the reed tanks need everything… green, red, blue, white, UV etc etc… without 1 of them they will die. we need the white beautiful light like the sun…. so coral tank full spectrum right ?

    Reply
  32. T Karcher Author

    I have asparagus ferns. They have long stalks and leaves like needles. Is that purple bulb good for my ferns? Or is the purple light just good for flowers?

    Reply
  33. AlboPepper - Drought Proof Urban Gardening Author

    LEARN MORE:
    Controlling Tip Burn in Lettuce: https://www.youtube.com/watch?v=gHWf4Hfi3hA
    Light Cycle Duration and DLI: https://www.youtube.com/watch?v=dQlOJ1zvoPI
    Red Light vs Blue Light & Plant Growth https://www.youtube.com/watch?v=sfihE4IuFuU
    Calculating LED costs vs payoffs: https://www.youtube.com/watch?v=Lhb4oK-9kNY

    LED Light growth tests:
    Infinity Linear (LED vs T5): https://www.youtube.com/watch?v=PfPmdKabemM
    UFO SMD vs Single COB LED w/ Time-lapse: https://www.youtube.com/watch?v=x7D3S2CYSPw

    Reply
  34. Howard Dibble Author

    Could use a led TV to grow it better by control of the light from leds that way? Each leaf get the maxim amount light study over time could control growth better;?

    Reply
  35. chris davis Author

    Hey, awesome stuff thanks! Do you have a recommendation for good and cost effective LED lights for vegetables—seed starting and growing herbs year round? Maybe some top Amazon picks? Keep up the good work!

    Reply
  36. N H Author

    Love your channel and videos! For this did you by chance measure your before and after water ratio? Just wondering it would be cool to know how much water is influenced by particular light colors as well. We already know the heat affected the CFL. Thanks

    Reply
  37. Billy Verve Author

    Green light has over an 80% absorption rate and is very useful in leaf light penetration and propagation.

    If you want a good grow light get one that closely mimics sunlight properties. You will not find that in a 200 dollar 1500 watt led light off Amazon.

    Reply

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