Mumbeltypeg
Well-Known Member
Green spectrum led has better penetration from what I have read but I imagine the difference would be negligible in reality.
Led yields..
- Thread starter Billytheluther
- Start date
Green also promotes more veging versus flowering.
"penetration" of…?
My impression is that marketing people use the term "penetration" to convince readers that light reaches further into the canopy. How that happens is never explained and, so far, I haven't seen any description of what Mars, Vipar, etc. actually mean.
In terms of "penetration" into a leaf, in at least one of Bugbee's videos, he puts up a slide and discusses the fact that green photons penetrate more deeply into a leaf than do red or blue photons.
And what that tells us is that green photons penetrate more deeply into a cannabis leaf than to red or blue photons. That's it.
As far as I recall, the most interesting thing about his discussion of how the different color photons is used is what Bugbee doesn't say. He has a slide that shows that blue photons inhibit cell expansion, red photons are cheap to produce, and far red promote cell expansion but when it comes to discussing green photons? The biggest issue (and this is from his "basics" video) is that it makes it easy for growers to actually see the plants, unlike blurples. In all of the Bugbee videos and papers that I've consumed, I don't recall him saying much at all about green photons.
"I imagine the difference would be negligible in reality." - hear hear.
I use separate veg and flower LED lights (Growcraft) and fill I with a Vipar XS 1500 + a Rapid LED Royal Blue puck for seedlings. I also have a Mars SP3000 and, for my current grow, added a paid of Spider Glow R80's (which are an excellent addition to any grow tent). The amount of green in the spectrum of those lights wasn't a factor in my buying them. If I could, in flower, I'd use a spectrum like one:
That's the spectrum from the Mars SP 3000R which is a new light for 2024 and is designed to be used in the flowering stage of plants in greenhouses. No surprise, the spectrum is very similar to the spectrum of an HPS bulb. Funny that.
pop22
Well-Known Member
It's not the lights, at least if it's a quality brand. It's long since been proven that LED lighting is superior to HID. Secondly, there is no way for HID to have better penetration when it's light output is non directional. With LED ALL the light is pointed toward the plants. I've been growing with LED for over 8 years now and you couldn't pay me to go back to dealing with HID.
cdgmoney250
Well-Known Member
I’ve posted about this a bunch in other threads already, but green wavelengths “penetrate” (absorbed photons) deeper into both leaf tissue and deeper into the inner (lower) canopy, than blue or red wavelengths. In leaf tissue, green light absorption is throughout the depth of the leaf tissue, whereas red and blue wavelengths are almost completely absorbed near the surface of the leaf tissue.
www.sciencedirect.com
This can stimulate more plant pigments than red/blue photons could on their own. At higher ppfd levels green wavelengths were shown to be of similar photosynthetic efficiency as red photons, so long as green percentage didn’t exceed about 25%.
pmc.ncbi.nlm.nih.gov
Addition of green light improves fruit weight and dry matter content in sweet pepper due to greater light penetration within the canopy
The use of artificial light to supplement natural light is essential for successful greenhouse winter production in regions with low natural sunlight …
This can stimulate more plant pigments than red/blue photons could on their own. At higher ppfd levels green wavelengths were shown to be of similar photosynthetic efficiency as red photons, so long as green percentage didn’t exceed about 25%.
Photosynthetic Physiology of Blue, Green, and Red Light: Light Intensity Effects and Underlying Mechanisms - PMC
Red and blue light are traditionally believed to have a higher quantum yield of CO2 assimilation (QY, moles of CO2 assimilated per mole of photons) than green light, because green light is absorbed less efficiently. However, because of its lower ...
pmc.ncbi.nlm.nih.gov
Great job bud ....
After almost i wanna say 10 years break i am getting back to growing ...
And planning to go LED route ...
Prior I use MH for veg and HPS for flower ...
Heat was a issue in summer months like crazy for me ... so LED i balive will help me with that ...
Never the less 5x5 and getting 4lb plus is great in my book ...
Back in a day I did perpetual route using Stinkbud system .... and I think I wanna go same route ...
Not sure yet ... ebb and flow tables looks appealing to me as well ...
Having Stinkbud system back in a day i had to reset my whole grow once ... when I had power outage unfortunately my plants roots didn't get any nutrients and water due to pumps not working and aero system as those r not forgiving when it's coming down to that ...
And I was doing what Stink was at the time ... essentially take my clone cuttings from veging plants before I flip them to flower and no need for mother's... so it was painfull and time consuming lesson ... from that point i kept my mothers in dirt and now in this run I am planning my mother's to have in dirt for that reason ...
Anyways I remeber when LED's just appeared in to a scene quite a few years back but yields ware way smaller with those back then ... I c is not the case anymore so I am excited about that ...
Allright brother .. good luck to u.
tstick
Well-Known Member
I've been bombarding my 3 X 3 tent with ~375 watts overhead and another 160 watts coming from side-lighting -all LEDs. It's more than I ever dared to use in the past. Plants love it. They don't seem to care about spectrum as long as they are getting photons -lots of photons. I mean, okay, they might not grow under yellow, fluorescent tubes or black lights or something obviously stupid, but, generally, they respond to the abundance of light and not whether or not the spectrum has slightly more red, green, blue (or whatever else) in it. Unless you grow the exact same plants over and over and over again and you provide the same, exact conditions every time, your results are going to vary under ANY spectrum, regardless.
Billy the Mountain
Well-Known Member
That's spot-on.
There's been a few studies confirming that as well, dating back from the 90s. It's one area where quantity trumps "quality". HPS lamps are a good example, a terrible spectrum doesn't prevent perfectly fine results, just less efficiently.
ttystikk
Well-Known Member
No it isn't. Go look at the spectrum curve of an HPS light and you'll see that it makes its massive spike in the yellow-orange to green part of the spectrum. It does emit a fair amount of longer wavelengths but that's mostly an artifact of how hot the damned things run.
Mumbeltypeg
Well-Known Member
And to you friend. It’s exciting using all this new tech.
420AD
Well-Known Member
The differnet spectrums have different leaf penetration, yes.
Also spectrum influences your plant shape.
Poltrack
Member
This ratio stay incomplete and don't mean much for a bunch of applications (com. grow, breeding, decisionnal).
You can have high gr/watts ratios and a pretty bad yield if time is not counted (it's watt/hour anyway the measurement ^^)
Take a SOGger in a 4x4, 600HPS. If he's not good, he will make around a third of oz per clone in the smallest pots. In this context, let's explain he's not good because fresh, so the number of plants is limited to 50 per 4x4. Fems or clones doesn't matter, even if seeds are harvesting a bit more in more time ...
So it's a ~pound/4x4 on let's say a typical Skunk flo : 60 days. It give around 0.83gr/watt.
But ~100 oz / year.
Take a grower that SCROG his weed, a good one take one harvest to prepare before the switch. So 120 days, in the average scrog-growlog it's a lot more in general.
So it's again a pound/4x4 that give again 0.83gr/watt.
But it's ~50 oz/year.
Also the SCROG-weed is lot more expensive than the SOG one, but it's generally never entering in considerations ^^
A bunch in fact, and i'm serious ^^.
It's the only way to know if you screwed the round with too much water in the vegetal mass (too much cycles), then bad drying stats. Then a good yield that transform in a bad one in drying, except if you sell the nugs barely dried lool ^^
cdgmoney250
Well-Known Member
Very few studies from back then (if any) were testing secondary metabolite production. Today they are, and results show significant differences in secondary metabolite production between different spectrums. I think we can all agree that cannabis is a high light loving plant, and that increasing light intensity almost proportionally increases total plant and bud dry weight, almost regardless of spectrum quality.
But, more recent studies show that cannabinoid content and terpene content can be manipulated by applying additional wavelengths or changing percentages or FR/R/G/B/UV within the spectrum.
Yield is important, but for me personally, quality is more important than yield. Total yield can be manipulated through a variety of garden practices. Increasing plant quality is seemingly more nuanced and difficult than just “turn up the light”.
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tstick
Well-Known Member
But, what plants were being studied in order to get the results? Some component of these tests has to remain almost perfectly consistent....and how do you get plants to grow consistently every time from plant-to-plant? Every time I've grown plants, I slightly alter the environment each time -depending on all the other extraneous conditions that vary from grow-to-grow. It might be slightly colder outside or less humid or more humid...etc. And that all affects the inside conditions, too. Growing conditions are constantly changing. And the test subjects need to be consistent so that you can determine the effects of the spectrum used.
If, for example, I grew ONLY Blue Dream, then I'd be able to study the results of using different spectrums on that one strain. But, as we all know, there are plants that grow tall and skinny and there are plants that grow short and bushy.
I don't care a bit about yield. My goal is to grow for smell and flavor....BUT....some plants respond to the exact same conditions in different ways. I'm growing Tuna Kush this run and it's supposed to be a low-yielding, short, bushy Indica. Somehow, I have dialed-in the environment that pleases it and it's growing bigger than it's supposed to. And in the other tent, I have Triangle Kush which isn't as happy with the environment.
I'm not saying that spectrum can't influence secondary metabolites in a positive way for some strains. I'm suggesting that no one grows plants in the ways that you have to do in order to do the testing. Therefore, the results of any given test are only relevant to the specific strain being tested.
Blue brother
Well-Known Member
I believe the less uniform distribution of photons across the canopy with hps drives more red photons deeper into the canopy directly under the light. I use both led and hps depending on the season, so I'm not biased, they both have their uses.
I'll just leave this here haha
I'll just leave this here haha
cdgmoney250
Well-Known Member
I've dropped a link to the studies I’m referring to from a previous post of mine.
click here ———> LINK TO STUDIES
I have only linked studies done on cannabis (some hemp, some drug type). These studies use cuttings from the same genetic stock ( some use multiple strains, tested different ways) and the test are usually replicated 3 times.
I get what you’re saying about results being impacted by variables, but that’s what the people doing these studies try their best to eliminate. No experiments are perfect, but that doesn’t mean that we can’t learn from the data gathered.
Secondary metabolites, pretty much the whole reason cannabis is cultivated, are affected and/or limited by the light spectrum. Doesn’t mean light is the only factor, it’s not. But it is certainly of primary focus because it’s an “easily”controllable variable. If a broader light spectrum enhances terpene and cannabinoid production more-so than a narrower light spectrum, then in my opinion, the broader spectrum is more desirable to use as a grow light spectra.
420AD
Well-Known Member
Gram per watt devided by the days times 100 I think would be a good way of taking the rate of growth into account.
For example:
1 gram per watt, 65 days total you'd get:
1/65x100 = 1.538
1 gram per watt, 75 days total you'd get:
1/75x100 = 1.333
1 gram per watt, 90 days total you'd get:
1/90x100 = 1.111
However you wanna call it... periodic grams per watt or whatever.