How light spectrum affects nutrient use in plant tissue...

PharmHand · Mar 21, 2017

GT21 said:
Photon colors hit photo system 1 and 2 and chlorophyll a and b differently which changes the cycle speed and the secondary metabolite usage. Has nothing to do with intensity.. in more intense light you use less nutes to prevent stoma gas off burns. Different light color makes a plant use nutes different.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3949401/

Unnatural light spectrum unnatural nute usage. Intensity would exacerbate any imbalances. Plants evolved to use the suns spectrum and can probably effectively use more light with a better CRI. But at the same time can only EFFICIENTLY use so much light. Studies show cannabis grows better at 1500umol or less. Having lights too close can easily exceed 1500umol. DLI must be considered too, in nature it ain't high noon all day long.....

PharmHand · Mar 21, 2017

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3550641/

GT21 · Mar 21, 2017

PharmHand said:
Unnatural light spectrum unnatural nute usage. Intensity would exacerbate any imbalances. Plants evolved to use the suns spectrum and can probably effectively use more light with a better CRI. But at the same time can only EFFICIENTLY use so much light. Studies show cannabis grows better at 1500umol or less. Having lights too close can easily exceed 1500umol. DLI must be considered too, in nature it ain't high noon all day long.....

This is a good point... your uv index and spectrum mix and intensity changes constantly outside moving through the arc of atmospheric particles. Indoors you drill a plant with the exact same light throughout

PharmHand · Mar 21, 2017

GT21 said:
Photon colors hit photo system 1 and 2 and chlorophyll a and b differently which changes the cycle speed and the secondary metabolite usage. Has nothing to do with intensity.. in more intense light you use less nutes to prevent stoma gas off burns. Different light color makes a plant use nutes different.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3949401/

From your link:
However, excessive light generates oxygen radicals and causes photoinhibition. Both phenomena strongly limit primary productivity [6].

GT21 · Mar 21, 2017

PharmHand said:
From your link:
However, excessive light generates oxygen radicals and causes photoinhibition. Both phenomena strongly limit primary productivity [6].

Are we talking about excess light or spectrum to nutrient balance? Excess heat effects the plant different than light color/spectrum

PharmHand · Mar 21, 2017

I'm just a stoner with a high school education and a passion for learning and growing I won't even pretend to know exactly how it works....That was from your link, I just kinda skimmed over it.... I'm gonna have to delve into it a little deeper to fully understand, that just jumped out at me. There's guys at IC BetaTestTeam that go into detail and actually know what they're talking about I'm just regurgitating what I've read.....
However from my own observations I've noticed plants can handle really high temps better without bright light simultaneously. Some really hot summer days it reached over 100f in my old room so I would turn off the hids and it would still be over 100 but it wouldn't cause any kind of damage. However if I had the brights on it would....

I've also noticed that parts of plants can handle super intense light/ higher heat for a few days before showing nute defs. I used to grow trees with 1k side lighting kept really close and if I rotated the plants every couple days so a new part of the plant was exposed to the intense light the exposed section wouldn't show deficiencies. But if I didn't rotate it the leaves would show the localized cal def Cap posted pics of earlier in thread. Just my observations, like I said I'm far from an expert :D

HankHill · Jun 7, 2017

Not sure if his has been said this far. Blue light is going to promote more chlorophyll. So to answer your question, the MH bulb producing your blue spectrum is increasing the amount of chlorophyll and leaf thickness on that side of your plant. That is why you HPS side is showing more signs of the problem. If you think of it more in area terms( I'll use sqft) the mh side is producing more "area" to divide the nutes in because more chlorophyll is being produced. Where as your HPS side has less "area" or chlorophyll so your cramming more nutes into a tighter space.

angelina · Oct 25, 2017

Maybe you can take down the HPS for a few days, and then check whether the sympton may disappear or not.
Too much reds are not benefit for plants. I has always beening using MH. Mars II 1600, Mars Pro II 320.... hahaha, I have five:love2:. Now I'm looking for a new light for my lovely girls, MH COB light has my attention, but also want a Unit Farm 80 LED light, my friend has one. Looks like quite well.:party1:

NorthernMich · Jan 25, 2018

Mr.X said:
Same here

that is rust fungi.. not a light problem.

prospero · Jan 27, 2018

I use 600 watt dual spectrum throughout grow. This is my 4th grow using same bulb and still burning bright. May keep this bulb as spare and get new one next grow. Only critisism is lamp can burn qìuite hot so need to keep temp in check.

sixstring · Feb 2, 2018

Pastor said:
Whatever you decide on, keeping a grow journal in handwriting will help you tune and refine technique for more favorable outcome as you get deeper down the rabbit hole

alot has changed in 4.5 years,specifically lighting indoors :happy:

45North · Feb 13, 2018

sixstring said:
alot has changed in 4.5 years,specifically lighting indoors :happy:

I agree, exotic spectrum controls are now available for LED. Learning curve is steep but the rewards are crazy! Less heat and power costs.

farmermari · Mar 5, 2018

I think I was able to grab few tips for my canna farm...kudos guys

lukem5 · Mar 13, 2018

I can say that I experience mediocre results when trying to veg 24/7 with sunlight, and moving indoors under LED at night. it seems they just don't "eat" the LED light once they have a taste of the real thing, but it keeps them in veg.

Im going to run a test where I veg 24/7 under sunlight/artificial. One will be 300w of LED, one will be ~50w of led, just see see if the higher wattage one grows much faster if at all. I think we're gonna be surprised!!!

45North · Mar 24, 2018

Artificial can do really well, but the outdoor beasts......

MissBotany · Mar 24, 2018

Capulator said:
So I have this tree I am growing and it is surrounded by (4) 1000w bulbs.

2 MH and 2 HPS.

Plant tissue (leaves) being pummeled with HPS light are showing what looks like a P deficiency (brown spotting, purple petioles etc)

Leaves hit my the MH do not show these symptoms. This is on the same plant.

So by this observation I am wondering if an HPS spectrum (more red?) causes the plant to take up more P...

Where the botanists at yo!? I am super curious about this.

plants contain light-absorbing molecules that absorb only specific wavelengths of visible light, while reflecting others. Various wavelengths are not all used during photosynthesis. There are five types of chlorophyll, two of them responsible for photosynthesis and they are both dependent on blue and red light for optimal absorption of energy. Hope this helps!

I should also add that there are a lot of other variables that can effect growth. I like the science of manipulating those variables to try to get optimal results!

weedtech · Nov 27, 2019

This almost seemed to go somewhere - but has languished.

I think something was missed in the original hypothesis - in that nutrient use is more dependent on the strain that most anything else. The relationship of spectrum would be tenuous at best. More to the point is transpiration rate - which affects delivered nutrition. The solution concentration is not something the plant can parse or filter effectively to just exactly what it needs. It has to take pretty much what is offered and convert the shit it finds useless into salts that get dumped, somewhere. And this is effected more by the other variables ( Humidity and Temp - compounded as VPD in measurement ) and C02 concentration ( affects the stoma size, directly related to moisture throughput ).

There are many moving parts. Why I think this is fun.

As an observation - I have seen some patterns in the data I have collected when I turn on my UV-B lamps. Interesting trends in humidity and CO2 levels that follow those lamps going on and off. So there is perhaps something here in the original question.

Joe Fresh · Dec 8, 2019

I've noticed this as well... my moms under 3kw of mh look healthy and kids with heavy feedings... but my plants in the flower rooms akwats struggle and I end up having to lower nutes ot flush.

Red and far red have the greatest impact on photosynthesis...causing the plant to drink more...
If the plant drinks more it will drink said nutrients that come with it... when the plant is pushed with more intense light or stronger red spectrum the plants will want to drink more water and thus the nutrient solution will have to be lowered to accommodate the plants that need more water.

Mh bulbs produce less intense light than hps... and being in the blue spectrum they will have the plants transpire less so they will be able yo handle a stronger nutrient solution

weedtech · Dec 10, 2019

Joe Fresh said:
Red and far red have the greatest impact on photosynthesis...causing the plant to drink more...

Take a moment and translate wavelength into physical properties. Red light and IR ( specifically ) are heat - that has direct effects on evaporation and effective VPD.

When you think about light energy - the goal is to supply the Daily Light Integral ( DLI ) and perhaps more, in some cases. DLI is measured in actual photons delivered - there are devices you can use in a greenhouse to measure and monitor this value. The value is important because if you cannot meet and exceed DLI, extra CO2 is not effective and becomes a wasted exercise.

Aqua Man · Dec 10, 2019

Interesting read I found here.

An Update on Plant Photobiology and Implications for Cannabis Production

This review presents recent developments in plant photobiology and lighting systems for horticultural crops, as well as potential applications for cannabis (Cannabis sativa and C. indica) plant production. The legal and commercial production of the cannabis ...

www.ncbi.nlm.nih.gov

How light spectrum affects nutrient use in plant tissue...

How light spectrum affects nutrient use in plant tissue...

PharmHand

PharmHand

GT21

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PharmHand

GT21

I like soup

PharmHand

HankHill

angelina

NorthernMich

prospero

sixstring

45North

farmermari

lukem5

45North

MissBotany

weedtech

Joe Fresh

weedtech

Aqua Man

An Update on Plant Photobiology and Implications for Cannabis Production

How light spectrum affects nutrient use in plant tissue...

How light spectrum affects nutrient use in plant tissue...

PharmHand

PharmHand

GT21

I like soup

PharmHand

GT21

I like soup

PharmHand

HankHill

angelina

NorthernMich

prospero

sixstring

45North

farmermari

lukem5

45North

MissBotany

weedtech

Joe Fresh

weedtech

Aqua Man

An Update on Plant Photobiology and Implications for Cannabis Production

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