Effect of different spectrum on plants' growth

L

love smoke1

New Member
:welcome:

Red - promote longitudinal growth, elongate stem and petiole, enlarge leaves,
but decrease chlorophyll contents
Blue - promote horizontal growth, thicken stem and petiole, increase chlorophyll
contents, improve the density of stomata of leaves
Orange - promote seeds germination and longitudinal growth
Green - promote the formation of oxygen during photosynthesis
Voilet - thicken leaves, resist extension of stem and leaves, help to form anthocyanin
Near infrared 720-760nm - speed photosynthesis rates, stimulate cell elongation,
important for bloom and seeds germination
White - supplement special spectra by combined with different spectra
Effect of different spectra on plants component content
Blue - the content of soluble sugar & total free amino acids is highest
RB - the content of soluble protein is highest, photosynthetic rate of leaves is highest,
sugar, carbon and nitrogen balanced distribution in leaves, crowns and roots
RBG - the content of total starch is highest
Orange or Yellow - the content of sucrose is highest, promote the formation of carbohydrate



Tips to follow hopefully, DIY your grow light:thanks:
 
Welcome to the forums!
While some of the information you posted is true to some extent, some of it is missing other elements, while some is completely false.

Chlorophyll actually has most of it's photoreceptors in the red wavelengths, 662 and 642 to be exact.

In those plants that do like light for seed germination 660nm light is the preferred method, not orange (730nm actually inhibits germination).

Oxygen production has more to do with the red and blue wavelengths used in the photosynthesis process in chlorophyll production than anything that green wavelengths do.

Again the sucrose levels are directly linked the the photosynthesis rate and therefore tied to red and blue, not orange and yellow. You will actually have the lowest rates of sucrose with green and yellow wavelengths. If you would like some website with links to studies and scholarly articles covering this information, I'll be happy to provide a link or 50
 
Hosebomber said:
If you would like some website with links to studies and scholarly articles covering this information, I'll be happy to provide a link or 50
Click to expand...

If you wouldn't mind sharing, Id love to see what information you have on wavelengths, spectrums, plants or whatever relates. For some reason plant lighting interests me most about growing. Id love to learn what you have to offer. :)

Do you have anything regarding fading/dimming light vs full intensity?

I may even have a few that you may enjoy as well.

If you want to send me your email in a PM, I'd be glad to email you the links and PDF's I have, not many but good finds :)

--------------------------------------------
Just to add to the conversation about light colors and effects on plants..


Green light also triggers Shade avoidance on plants which increases stem growth, enlongates petiole growth, and even re orients the leaves in a different posture. When IR is present with Green light, then the effects are minimal to none of the green light. Typically this is a reaction to the leaves under the plant canopy where green light is reflected in the majority.

and this one too..

Blacklight: used after your buds are harvested to enhance the effects of Cannabis visual stimulation :) Ha.
 
Im Not Here said:
Some information on this link helped me

Light, Spectrum & Cannabis

Thank you,
Click to expand...
Realize where the information is coming from. The following is direct quotes from their website:

"Chlorophyll A peaks at 430 nm blue and 662nm red"

"660 nm Deep Red: Best for Night Interruption
730 nm Far Red: Promotes Flowering of Short-Day Plants (Not Photosynthetically Active)"

I'll pose a simple question to you. How can the peak receptor for the largest chlorophyll group be best for night interruption?
730 does promote flowering... to the extent that it is the night interruption photoreceptor. However, the Pfr reaction occurs via 730 so it is photosynthetically active.
 
Hosebomber said:
Here are a few of my favorites:
Contents
Oxford Journals | Life Sciences | Plant and Cell Physiology
Plant Physiology
H.Smith - PHYTOCHROME-MEDIATED RESPONSES
Usage and control of solid-state lighting for plant growth
Properties of Light | PVEducation (use the links on the left to navigate through the information)

Inside each you will find multiple links and or a searchable database for articles.
Click to expand...

Thanks Hosebomber for taking the time to share your links! Much appreciation.
 
Icemud said:
and this one too..

Blacklight: used after your buds are harvested to enhance the effects of Cannabis visual stimulation :) Ha.
Click to expand...
very funny.

Spectrum is only 1 important light factor in plant growth but useless data without the relationship to others. I and most people use a combo of 4 measurement of light; quality, quantity, direction and duration. The best way ive found to measure these are their shorthands; nm, umol, direction/distribution and DLI/photoperiodism. Without the addition of all 4 factors in the light, your like the blind men touching and describing a different part of the elephant. Let me give an example to spectrum...

Lets assume that blue stunts and red stretches but that is only true if there is a threshold of umol of certain blue wavelength is met. My guess is all species have different threshold numbers but ive read research in lettuce and basil whereas ~40umol of blue is enough to cause this stunting but anything more than 40nm, no matter the #red, didnt have an effect. Thus the threshold to get the blue effects is ~ 40nm. While more blue contributes to photosynthesis, it didnt contribute to photomorphogenesis.

To give my babble some simple growroom conclusions... i think most people have noticed that no matter how many umol of full spectrum LED's or MH or CFL or... they have pumping into their room, the plants wont ever stretch like an HPS because full spectrum means the threshold umol of blue has been exceeded and apparently HPS doesnt (thus the yellow-red colored light). So dont overdo the LED intensity thinking your plants are gonna get bigger because your fighting the blues, which isnt necessarily a bad thing. Becuz bigger isnt always better, at least that is what i keep telling the mrs.
 
Hosebomber said:
Here are a few of my favorites:
Oxford Journals | Life Sciences | Plant and Cell Physiology
Usage and control of solid-state lighting for plant growth
Properties of Light | PVEducation (use the links on the left to navigate through the information)

Inside each you will find multiple links and or a searchable database for articles.
Click to expand...

Here are a few I had saved, most of the info was in PDF format saved on my HDD...

Green light: a signal to slow down or stop

Plays of Rays: A Complete Idiot's guide to understand LED

Sunrise, sunset, daylight in a graph


<!--Can't find substitution for tag [blog.pagetitle]-->
 
Hosebomber said:
Green light: a signal to slow down or stop was an article that I had not seen and backs up nearly everything I have been saying about green light for years... love it!
Click to expand...

I love the part about the green laser light treated seeds! Producing more biomass!! Thats awesome!
 
Hosebomber said:
Green light: a signal to slow down or stop was an article that I had not seen and backs up nearly everything I have been saying about green light for years... love it!
Click to expand...
Meta analysis like this one is great because it brings together concepts from lots of papers with the additional benefit of offering a huge number of cites to chew thru.

I also havnt read this paper and am now contemplating my decision on allowing for a few whites% in my fixtures in the past because i thought it couldnt hurt except for a few watts and perhaps helped by exciting unknowns. Im currently ordering some 5% x 440nm, 49% x 640nm, 50% x 660nm and 1% x 735nm fixtures based on the paper High-power light-emitting diode based facility for plant cultivation which now seems like a spot on spectrum. I plan to supplement the 'blues' as needed and use this spectrum thru all growth phases as my main umol source.
 
Hosebomber said:
I would suggest widening your spectra as much as you can. With your current ratios, you are leaving out most of the non-photosynthetic processes we know about, let alone all of those we only guess of or have hints about.
Click to expand...
I have a few different 'full spectrum' fixtures, one type is topledgrowlight 3w x 100. These fixtures give me results that seem similar to MH grows except for a few less watts/g as well as alot less heat. I think they are good enough for most growers and seem an inexpensive way to enter into a fuller spectrum LED fixture. But Im looking to push some envelopes, im also growing more than just MJ so I would like to go back to the 9:1 to 19:1 red:blue ratio and work my way forward adding spectrum as i see need for.

But this brings up a good question, what ought to be the spectrum and ratios for MJ? If 9:1 isnt the best, what ought it to be and at what umol?

I also have no experience with the new full spectrum COB 380-840nm LED's, has anyone else?
 
I have yet to see those COB's, but anything beyond 750 is not known to create photosynthesis. As for a 9:1 ratio, I have not seen any indication that the ratio is even remotely close to optimum. I would venture to say it's closer to 6:4 but in that 4 I would include all other wavelengths.
 
Hosebomber said:
I would venture to say it's closer to 6:4 but in that 4 I would include all other wavelengths.
Click to expand...
Dude, you r the man. I just was reading you are in the 'industry' and by answering our questions and giving your highly informed opinions is really a gift to all of us. Please be sure to make a living too...
 
Hosebomber said:
the TopLED ... should still be close.
Click to expand...
From what i see, your 60r:40other is about what the topLED full spectrum is roughly running. Without a spectrometer, its hard to know for sure.

I have been adjusting my Apogee PAR meter (ele setting) by x .6 to come up with umol required to compare the full spectrum topLED to both T5 cool white and HPS hortilux 600w. If I want 1000umol of HPS, I need to replace with 600umol of topLED. Ive read that a few full spectrum lighting companies are using a conversion of ~ .5. What conversion are others doing?
 
For my panels, Apogee simply doesn't work very well. Their meters have huge errors in anything over 660nm. The following is the correction amounts for Apogee sensors and LEDs:


LED Electric Calibration Error [%]
Blue (448 nm peak, 10 nm FWHM) -10.7
Green (524 nm peak, 15 nm FWHM) 5.8
Red (635 nm peak, 10 nm FWHM) 4.7
Cool White -4.2
Neutral White -6.1
Warm White -9.9
Red, Blue Mixture 2.7
Red, Green, Blue Mixture 3.5

This is a link to their lecture about LED lighting errors in readings https://www.apogeeinstruments.com/content/Quantum Sensors-LEDs.pdf

As you can tell, all companies have an issue with reading the info properly. If you really want to get an accurate reading you have to use a spectroradiometer.
 
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