How Many Watts Does the Average 1K HPS Convert to Infra-Red?

Douglas.Curtis · May 2, 2019

I've been using HPS lighting for over 15 years now and never really gave this question much thought. While I understand there are many types of 1000w HPS lamps available, I'm looking for a general average. Out of the 1000 watts powering a 1000w HPS lamp, approximately how many watts are converted directly to infra-red energy?

The second bonus question (no, I do not know the answer to either of these. I looked, but have not found it yet.) is, approximately how much of this infra-red is the average cannabis plant capable of converting to plant matter and cannabinoids/terpenes?

Lost in a SOG · May 2, 2019

My guess, looking at images of hps spectral output is around 3-5% is IR..

Imo, IR will act more on circadian like signalling pathways and this is why far red and into the IR as well as plent red is cited as helping boost the emerson effect whatever that is in reality.

In nature plants receive a blend of the full spectrum that changes constantly as the aspect and elevation of the sun changes..

Ibechillin · May 2, 2019

Most spectrum charts only show the PAR range instead of all the spectrum it is producing (I have accurate HID spectrum charts in the light science thread in my signature). Gavita says HPS emits ~55-58% of its spectrum in infrared light, MH and CMH would be near that as well. This is probably the reasoning behind recommending replacing 1000w HPS with ~600W of quality led. Robert Emerson proved that there are 2 different photosystems active in plants that absorb different parts of the light spectrum. Photosystem I absorbs and reacts with light above 680nm (the infrared photosytem), Photosystem II absorbs light below 680nm (UV and visible spectrum). He discovered this by testing how plants responded to different spectrums of monochromatic light (one wavelength/color only). He noticed between 660nm - 680nm red light wavelengths only the photosynthetic activity was highest and declined above and below those wavelengths. Then he experimented exposing the plant to the max photosynthetic active range (660nm-680nm red) and far red 700nm simultaneously and photosynthetic activity increased exponentially. Chlorophyl A absorption peak is 662nm and provides the most usable energy for growth and is also in the Photosytem II max activity range (660nm - 680nm).

Emerson Effect On Photosynthetic Ability Example:

Funny you would ask this question today, just yesterday I was researching into using different wavelengths of far red instead of only 700nm to see which had the largest improvement on photosynthetic activity. :biggrin:

Here Is Link To A Study Im Currently Reading:

https://www.researchgate.net/publication/273057363_Far-Red_Spectrum_of_Second_Emerson_Effect_A_Study_Using_Dual-Wavelength_Pulse_Amplitude_Modulation_Fluorometry

Relevant Excerpt:

FRIFS = Far Red Induced Fluorescence Shift

The involvement of PSI in the FRIFS phenomenon as a factor limiting the non-cyclic electron transport is clearly confirmed by the fact, that in our experiments FRIFS has a lower value when the fluorescence was excited by red modulated light instead blue light (FRIFS = 2.5% under 640 nm light and 11.8% under 470 nm light-both at 0.1 µmol photons m–2 s–1). It should be noticed here, that blue light at 470 nm preferentially excites PSII, whereas 620-640 nm light excites both photosystems nearly equally (Hogewoning et al., 2012).

Here are results of 470nm blue along with different far red wavelengths:
(It appears that the largest increase in Photosynthetic activity comes from mixing blue light ~470nm and infra red light at 720nm simultaneously).

Lost in a SOG · May 2, 2019

Wtf 50+% of the energy in IR thats crazy.. my original guess was 10% but that would be insanely efficient thinking about it.

Ibechillin · May 2, 2019

Updated my above post.

Lost in a SOG · May 3, 2019

An example of how the suns output changes throughout the day.. the changes in relative spectrum on plants, like all life, has powerful effects on signalling pathways that effect epigenetic changes. This drives greater hormone synthesis for bigger flowers regardless of how much photosynthetic energy is being created through the IR as a stand alone factor. But plants do also expect a certain amount of heating up of their photosynthetic apparatus that would occur alot through IR from the sun.

Adding too much throughout the day will probably make the plant think it is shaded too much and stretch more than you want as id imagine IR being beyond far red is also perceived as shading by plants but im not 100% on that.

I still think it is about overall balance you create and at what time of their day.

Ringodoggie · May 3, 2019

My Raspberry Pi sensor separates IR from the rest. Here is how it looks. This is a 1000w HPS. Looks like about 30% is IR.

Ringodoggie · May 3, 2019

Here is another shot of my other tent. This one has 15 T5 bulbs and a Mars blurple LED. Looks closer to 20 - 25% IR.

Koondense · May 3, 2019

Lost in a SOG said:
View Image

An example of how the suns output changes throughout the day.. the changes in relative spectrum on plants, like all life, has powerful effects on signalling pathways that effect epigenetic changes. This drives greater hormone synthesis for bigger flowers regardless of how much photosynthetic energy is being created through the IR as a stand alone factor. But plants do also expect a certain amount of heating up of their photosynthetic apparatus that would occur alot through IR from the sun.

Adding too much throughout the day will probably make the plant think it is shaded too much and stretch more than you want as id imagine IR being beyond far red is also perceived as shading by plants but im not 100% on that.

I still think it is about overall balance you create and at what time of their day.

This graph shows relative irradiance and it makes it look like there's more red light at dawn compared to noon. Those lines should not be put on the same relative axis but on an absolute irradiance plot.
Also I'd love to see the graph for 8am or just a hourly change graph, to get to know how significant effect is this. I think it's not so important at all.

Cheers

Ibechillin · May 3, 2019

I dont trust the accuracy on the raspberry PI spectrum reader, also its measuring lumens/lux which weight the wavelengths of light differently depending on how well the human eye perceives it which could explain showing the ~30% IR down from actual 55-58% IR.

Another interesting thing Gavita mentions about growing under led with minimal IR is needing to increase nutrient strength by up to 25% compared to HPS since the plants dont transpire as much. Here is the link to the Gavita editorial on LED that I found the 55-58% IR spectrum from HPS.

Gavita Editorial On Led:

https://gavita.com/retail/app/uploads/Garden-Culture-editorials-4.pdf

I posted this on 2-6-2019 in DC's optimal spectrum thread:

Link to DC's optimal spectrum thread:

https://www.icmag.com/ic/showthread.php?t=359554

Ibechillin said:
The research ive done on far red lighting suggests you only need the high far red ratio to simulate the sunset conditions outdoor during the last ~30 minutes of the lights on period for the stretch response.

In the link I attached at the bottom it explains daylight is around a red:far red ratio of 1.15 (15% more red light) to 1.37 (37% more red light). At sunset the red:far red ratio is closer to 0.7 (30% more far red light).

The link explains that by covering greenhouses with blackout tarps before the high far red sunset lighting reaches the plants final height could be reduced up to 25%.

Link to study on red:far red ratio and plant growth:

https://journals.ashs.org/hortsci/view/journals/hortsci/42/7/article-p1609.xml

Douglas.Curtis · May 3, 2019

Wow... thank you for all the contributions, this has certainly been enlightening. I'm in absorbing mode again... lol

Ibechillin · May 3, 2019

Forgot to mention the higher ratio of infrared light at sunset is also why outdoors plants will flower around 14hr days since it triggers the phytochromes to Pr flowering state right before dark.

Ibechillin · May 3, 2019

Speaking of spectrum/phytochromes/flowering I learned something interesting last week from Ed Rosenthal's Marijuana Growers Handbook I wanted to share.

Ed Rosenthal said:
Plants use blue light to regulate flowering as well as for photosynthesis. Blue light is not as efficient a source of energy for photosynthesis as red light indoors because blue light has a higher energy value than red light and it requires more
energy to produce than red light. However, the plant obtains the same amount of energy from both of them.

Ed Rosenthal said:
Blue light is another option for sexing. As mentioned earlier in this chapter, marijuana flowering is very sensitive to red light of specific spectrums. Any interruption of the dark period with light that contains the red, 660 nm spectrum returns the flowering hormone Pr back to its inactive state, Pfr. This prevents flowering.

Blue light at 400-450 nm also has an inhibitory effect on flowering, but its effect is weaker than red light. Plants grow some flowers when blue light is kept on during the dark period; however, they continue to grow vegetatively as well. If you use blue LED or fluorescent lights to provide the plants with nothing but pure blue light, they will get enough stimulation to produce some flowers for sexual identification but not go into full flowering mode. Once all the plants indicate, replace the blue light with a full spectrum light period to keep the plants growing vegetatively. When blue light is turned on during the dark period, plants photosynthesize, but the growth from the blue light is not significant. The stems grow a little more stocky. See the Phytochrome Response chart, which shows phytochrome Pr-Pfr sensitivity across the light spectrum. The red-far-red portion shows high activity. The blue spectrum shows just a little bump. This indicates a slight activity. The result is sporadic flowering on all the plants. You can create a pure blue light with LEDs and blue CFLs. Use about 200 watts of mixed blue light per 1,000 watts of regular light. I have done only initial experimentation with this so test this in a limited way first.

Lost in a SOG · May 3, 2019

Koondense said:
This graph shows relative irradiance and it makes it look like there's more red light at dawn compared to noon. Those lines should not be put on the same relative axis but on an absolute irradiance plot.
Also I'd love to see the graph for 8am or just a hourly change graph, to get to know how significant effect is this. I think it's not so important at all.

Cheers

Ahh my bad..under further inspection that was from a study looking at the effect of morning IR on human skin photoprotection from UVs.. really interesting actually, turns out dawn light readies and protects us.

I think this is an hourly one.

Lost in a SOG · May 3, 2019

Wow triple posted :smoker:

Lost in a SOG · May 3, 2019

Koondense said:
This graph shows relative irradiance and it makes it look like there's more red light at dawn compared to noon. Those lines should not be put on the same relative axis but on an absolute irradiance plot.
Also I'd love to see the graph for 8am or just a hourly change graph, to get to know how significant effect is this. I think it's not so important at all.

Cheers

Ahh my bad..under further inspection that was from a study looking at the effect of morning IR on human skin photoprotection from UVs.. really interesting actually, turns out the dawn IR light readies and protects us from UV damage.

Im curious what you dont think is important?

Ibechillin · May 3, 2019

This is AM sun spectrum change:

Noon Daylight D65 is what plants are exposed to in full sun, comprised of direct sunlight and light being reflected/diffused from the surface and other objects, Noon Sunlight D55 is like a ray of light into a dark room, Sunset Sky self explanatory haha.

St. Phatty · May 3, 2019

I LOVE THIS QUESTION !!!

but I don't know the answer.

I spilled a pint of boiling water on my left forearm.

I think it sort of knows the answer.

f-e · May 4, 2019

A rough rule of thumb for hid's in general is 25% light, 25% conducted and convected heat, and 50% IR. They're essentially heaters, getting so hot they give off light.

Leds Lower the IR a lot, but increase the heat lost through conduction and then convection buy a similar amount. The heat is still there. It's just handled differently. This is proven when you look at the 25% that is actually light. Both a decent HID and most Led's are making about 150lm per watt. All the rest of the power is heat. IIRC the very best leds, so expensive we arn't getting them, are turning 35% of the power to light. Leaving 65% as heat. Mostly conducted away from source though, not radiated.

Loc Dog · May 4, 2019

Someone suggested to me, 15Watt IR bulb last 10 minutes of light during flowering, and 10 minutes after lights go out.

How Many Watts Does the Average 1K HPS Convert to Infra-Red?

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