Science Advances In Matching Led Lighting To Horticultural Needs

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Great article. After review of the information in this article be sure to follow the posted link at bottom of the page to visit LEDS magazine. Excellent resource for all things LED. White papers, studies, suppliers, mfgrs etc.

Published on:September 20, 2016
By Maury Wright
Editor in Chief, LEDs Magazine
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LED-based SSL products are bringing revolutionary advancement to indoor and greenhouse growing operations, explains MAURY WRIGHT, but there remains much to be learned about the differing light needs of varying plant types and even how needs change during a growth cycle.

High-power LEDs are bringing similar revolutionary benefits in life-science applications such as horticulture that the solid-state lighting (SSL) sources are offering in the general illumination area -energy efficiency, low/no maintenance, spectral control, and beam control. But plants need different things from light relative to people, and human-oriented metrics such as efficacy (lumens per watt - lm/W) or CRI may or may not provide any indication as to whether an LED luminaire will deliver results for vegetable and flower growers. Moreover, plants have circadian cycles that differ from those of humans and that vary widely from plant species to species. Still, growers are quickly moving to SSL in greenhouses and especially in indoor urban or vertical farms while the horticultural community is working overtime to decipher the needs of plants in terms of light recipes for optimal growth and yield.

1609LEDSF3_fig1.jpg


FIG. 1. Green Sense Farms grows micro greens, lettuces, baby greens such as kale and watercress, and herbs in a Chicago-area vertical farm that can deliver the fresh produce to buyers on the day of harvest.

SSL could truly revolutionize the global horticulture industry including edible produce and the similar floriculture or flower-centric industry. LED-based lighting will also play a critical role in cannabis growing, especially as the legal climate evolves for both medical and/or recreational marijuana usage. Indeed, the growing significance of LEDs in horticulture led us to plan our inaugural LEDs Magazine Horticultural Lighting Conference slated for Oct. 12; further details can be found below.

SSL roles in horticulture
The use case for LEDs in fruit and vegetable farming centers around extending the growing season, especially in cold regions with short summers. Artificial lighting, primarily high-pressure sodium (HPS) lighting in the past, has long been used in greenhouses to extend tomato seasons, for example. We will discuss what LED lighting adds to the story throughout this article, but one clear advantage of SSL is the fact that the lighting produces no heat and growers can use interlighting - placing lights near/between the plants, run either vertically or horizontally to deliver light to the lower foliage that doesn't receive much direct light from above as the plant grows.

The greenhouse use case for LEDs is primarily as a supplementary light source to the sun, although the artificial lighting is increasingly vital during the colder and shorter days of winter. Cannabis also requires greenhouse-like space where plants can grow vertically. But most legal cannabis growing operations are for now indoors, and require electrical fixtures as the primary light source.

Where LEDs are having the greatest impact, however, is in growing leafy greens and herbs that only reach heights measured in inches and that can be grown in layers or racks with each layer having a dedicated set of LED luminaires relatively close to the plants, again enabled by little to no heat radiated by the LEDs. The layering enables so-called urban or vertical farms to occupy relatively small growing spaces inside buildings near population centers, while optimal lighting and technology including hydroponics enables much faster plant/harvest cycles than can be achieved outdoors.

The range and scale of such operations is amazing. Our cover photo for this issue shows a Local Roots vertical farm housed in a used shipping container. The company is a Los Angeles, CA-based grower of leafy greens and herbs. Fig. 1, meanwhile, depicts an industrial-building-scale vertical farm operated by Green Sense Farms in Indiana, a short drive from the Chicago, IL metro area.

1609LEDSF3_fig2.jpg


FIG. 2. Spectrum King LED luminaires use predominantly white LEDs and are regularly sold into legalized medicinal or recreational cannabis growing operations indoors.

Urban farms
Indeed, it is perhaps the urban farms where LED lighting may have the largest impact on horticulture, and it wouldn't be a huge stretch to say that impact extends to global society and the environment. The ability of growers to operate in high-volume vertical farms in any city means that the transportation cost will be slashed relative to the cost associated with farming in remote areas such as California's Central Valley. Consumers will get access to produce in some cases the day it's harvested and the product will have a far greater shelf life. And there will be immeasurable reductions in the carbon footprint associated with farming, both due to short transport and elimination of carbon-producing outdoor machinery needed for traditional farming.

The benefits of LED horticulture to the consumer run deeper - and tastier. We will discuss later the qualitative opinion of many that produce grown under LED lighting tastes better. That may be a judgment call, but fresher produce almost always tastes better. Furthermore, urban farms provide consumer access to micro greens and herbs that just might not be available otherwise. Green Sense, for example, grows plants such as baby kale, watercress, arugula, and more along with herbs like basil and thyme. The urban farms also are generally pesticide free and the yield may not even require washing given that it's often grown hydroponically in clean media and not dirt.

The growing methodology is extremely water efficient, and that's a major issue in regions such as California where the farming-centric Central Valley is relatively close to Los Angeles and San Francisco, but the state is in a persistent drought. In other areas globally such as China, the groundwater and/or soil is polluted and there is little other way to produce safe and tasty produce.

1609LEDSF3_fig3.jpg


FIG. 3. Local Roots constantly adapts its LED lighting in shipping-container-based farms for optimum production of leafy greens.

Challenges in horticultural lighting
There are, of course, challenges in any emerging technology and perhaps even more so in LED-based horticultural lighting where experience with SSL technology is still shallow, and even the long-involved horticultural scientists are still developing research on light recipes for plants - and some of those new recipes weren't feasible prior to LED sources with controlled spectrum entering the picture.

Lighting manufacturers based in Asia have targeted the market with what are often affordable but low-end products, but many of the low-end products on the market lack pertinent certifications such as UL ratings, as well as LM-79 reports for fixtures and LM-80 reports for the LEDs used in the fixtures, said Rami Vardi, CEO of Canoga Park, CA-based lighting manufacturer Spectrum King. Vardi said many growers, especially in the cannabis sector, have been burned with early attempts to deploy LED lighting due to poor fixture performance and that HPS remains the gold standard for that industry.

Certainly, there are many high-quality lighting products on the market as well, including those from stalwarts such as Philips Lighting, Osram, and Hubbell Lighting. Both Osram and Philips have spent years on horticultural research working with university and dedicated-research-organization teams.

1609LEDSF3_fig4.jpg


FIG. 4. AeroFarms in the New York area uses an aeroponic methodology to grow leafy greens in which the roots are exposed to only a mist for even more-water-efficient farming than hydroponics.

Still, the growers across the horticulture and floriculture space need both better metrics that are pertinent to the application and access to data on light recipes. As we covered in an article last year, the American Society of Agricultural and Biological Engineers (ASABE) Agricultural Lighting Committee began in 2015 to work on the standardized metrics issue. The work is considering metrics related to the PAR (Photosynthetically Active Radiation) spectrum among others. The PAR range is generally defined as the 400-700-nm spectral band where photons actively drive photosynthesis. Common metrics related to PAR include Photosynthetic Photon Flux (PPF) measured in micromoles per second (μmoles/sec) and Photosynthetic Photon Flux Density (PPFD) measured in μmoles/m2/sec where a mole can be directly converted mathematically to photons.

Recipes and metrics
Let's consider the inherently-intertwined issues of recipes and metrics because growers clearly need metrics that can discern whether a luminaire delivers the intensity and spectral power distribution (SPD) mix that comprises a recipe to optimize yield.

When we covered LED lighting in horticulture back in 2011, the key message was centered on research that documented chlorophyll absorption relative to spectral power because chlorophyll is key to the photosynthesis process. Laboratory research had indicated that energy peaks in the blue and red spectrum matched absorption peaks, whereas green energy was shown not to impact absorption.

That early research resulted in the plethora of fixtures on the market that emit pink or purplish light based on the use of monochromatic red and blue LEDs. The pervasive theory behind those products centered on energy efficiency and this question: Why should luminaire designs generate energy outside those bands if that energy would simply be wasted on the plant?

Current thinking, however, centers on lighting that can deliver peak energy in the blue and red spectrum but that also delivers a broad spectrum much like sunlight. Paul Scheidt, LED product development leader at Cree, said, "The industry seems to be moving more to white light."

1609LEDSF3_fig5.jpg


FIG. 5. The Philips Lighting GreenPower LED Production Module includes a mix of red, far-red, blue, and white LEDs to dynamically deliver what the company said are the primary colors for plants.

White light matters
Others have made more forceful statements. Neil Yorio, vice president of Biological Innovation and Optimization Systems (BIOS), commented on the topic; his company is working on LED luminaires for cannabis and other sectors. "The use of only red and blue LEDs is pretty outdated, and when you see products with that spectrum, it is based on older science and is frequently misinterpreted," said Yorio. "The reason people have chosen blue and red is because these wavelength peaks align with the absorption profile of chlorophyll a and b isolated in test tubes. That is not what is happening in intact leaves. We know today that all wavelengths of light in the PAR range are useful in driving photosynthesis. No doubt spectrum has importance, but it is associated with plant morphology such as size and shape rather than growth and yield or biomass."

Yorio's point is that research shows we can impact plant height and flowering by changing the spectrum. And as we will discuss a bit later, some growers continuously modulate light intensity and SPD mix to plants as the plants do have something akin to a circadian rhythm, although most every plant species has a unique rhythm and recipe requirement for optimal yield.

Vardi of Spectrum King said the predominant red and blue mix might work relatively well for leafy greens such as lettuces. But he also said flowering plants where biomass is the goal, including tomatoes and cannabis among others, require intensity more than specialized spectrum. Vardi said 90% of the energy in HPS lights is in the yellow region, and that lumens (lm), lux (lx) and efficacy may be more accurate than PAR-centric metrics in horticultural luminaires for flowering plants. Spectrum King uses 90% phosphor-converted white LEDs in its luminaires with the remainder being red or far-red LEDs. Vardi said the blue emitters that are the basis for white LEDs deliver all of the blue energy required for optimal production. The products depicted in Fig. 2 are in the traditional form factor of an HPS lamp.

Even in vertical farms where the focus is products like lettuce, it appears that some white light is a requisite, although you can see via photos in this article that the bulk of the LED light produced remains pink to purple in nature. Robert Colangelo, founder and CEO of Green Sense Farms, will not share details of his company's light recipes as the recipes are considered key intellectual property (IP) for the business operation. But he said the farm has used various mixes of red, blue, and white light in growing lettuce, micro greens, baby greens, and herbs. Green Sense has been described in some mainstream media articles as the largest indoor commercial grower. Colangelo said it's difficult to quantify scale, but the company's first farm in Indiana has 8000 4-ft linear LED fixtures and the latest farm in China has 3500 8-ft fixtures.

Recipes and impact
White light can be important for reasons beyond baseline production in leafy greens. Several people we interviewed for this article said lettuce may not mature to look green without some light from the green spectral band. On the other hand, sometimes growers may control the spectrum to create new colors in produce. Gus van der Feltz, global director of city farming at Philips Lighting, for example, said you may want to grow a specialty lettuce with a red coloration. Also, white light is required at times for workers as we mentioned in a prior horticultural lighting feature, and as stated earlier the blue energy peak in white LEDs is a plus.

1609LEDSF3_fig6.jpg


FIG. 6. The Innovatus farm located in the Fuji area of Japan produces 12,000 heads of lettuce each day.

Clearly, there is no consensus on light recipes, and researchers and growers are constantly striving to advance the science. Colangelo said, "We do constant research on light recipe per cultivar." Philips' van der Feltz said the recipe invariably must be different for each plant but added, "You can modulate the growth process." The point is that changing the light during the growth stages can make significant differences in the same species. In the article referenced just above, we covered some research on using far-red spectrum to impact flowering, for instance. Matt Vail, co-founder and COO of Local Roots, said, "We change the light on an hourly basis." Fig. 3 shows a Local Roots container with LED lighting evident through the doorway.

The recipe-development process is painstaking. Philips' van der Feltz said the company's research team investigated a single variety of strawberries over nearly a year, using different mixes of red, far-red, blue, and white light. But through that lengthy endeavor, ultimately the team found a recipe that delivered a 20% difference in better taste and juiciness.

What growers want
As the commercial LED-lit horticultural installations mature, there will be more certainty about what growers want from SSL manufacturers, although today that topic remains a bit of a mystery. Robert Colangelo from Green Sense identified four key things. First, Colangelo wants quality products that maximize the ratio of dollar per joule (a unit of energy or work done) per μmole. Second, he wants a lighting product that enables the farm to use a different light mix for each cultivar. Colangelo said Green Sense has not found a benefit to dynamically changing the lighting during the growth cycle but needs a different recipe for each species. Third, he cited ease of installation and noted that the company has moved to 8-ft luminaires from 4-ft luminaires because installation effort is essentially cut in half relative to the area covered. Fourth, Colangelo cited affordability and financing as important because he said lights are the most expensive element in a vertical farm.

Not all commercial growers have found what they need from commercial LED lighting manufacturers. Local Roots, for example, has designed and begun to manufacture a custom LED luminaire in a rectangular form factor for its operations. The company is equipping its used shipping containers to house a complete farm with one container having the ability to produce the equivalent of what a 5-acre traditional farm would produce. Local Roots powers its luminaires with DC, relying on a single AC circuit to the container. Vail said the design mixes monochromatic and white LEDs, and the customized control system can enable 0-100% control of the intensity of each LED. As we have covered in articles on DC power distribution, the architecture should also deliver additional energy efficiency relative to powering each fixture with AC.

1609LEDSF3_fig7.jpg


FIG. 7. A French tomato farm uses Philips fixtures for interlighting between rows of plants to deliver needed spectral energy to the lower foliage of each plant.

Of course, all of the urban farmers we interviewed stressed that the horticultural problem requires a system-level approach that goes beyond lighting. These large urban farms typically implement complete environmental control with computers measuring things like temperature and humidity, and controlling hydroponic feeding along with the lights.

Moreover, the operations develop partnerships that are often governed by IP protections. Green Sense, for instance, uses a unique growing medium fashioned from coconut husks. A New York area farm called AeroFarms (Fig. 4) created a custom substrate or growing cloth medium made from recycled water bottles. And AeroFarms uses what it calls an aeroponic system that sprays mist on the roots, which the company said uses 40% less water than do hydroponic systems.

LEDs enable vertical farming
Still, it's the LED technology that has truly made vertical farming pay off. Colangelo of Green Sense said LED lights enabled the vertical concept to go from pilot to commercial. He said growers could go from seven to eight layers with linear fluorescent lighting to 12 to 14 layers with LEDs in a building with, say, 25-ft-high ceilings. LED efficiency and the lack of radiated heat were the key enablers.

The lighting and LED manufacturers, meanwhile, are working diligently to deliver products that enable growers to succeed. Cree, for example, recently announced what it called a Photo Red LED in the far-red spectrum that might be useful in encouraging flowering. Spectrum King is apparently using that LED in its fixtures.

Philips Lighting recently announced what it calls the GreenPower LED Production Module which, despite the name implying a module, is a finished linear fixture that has been added to the GreenPower family of products. The new product (Fig. 5) integrates a mix of red, far-red, blue, and white LEDs and comes with software for programming light recipes. "Red, blue, white, and far red are the primary colors for a plant," said van der Feltz. And the new luminaire can mix those colors just like an RGB fixture delivers a full spectrum for the human eye.

The GreenPower LED Production Module is intended both for growers to work on light recipes and for growers to use in commercial farms when dynamic lighting is deemed beneficial. For example, Philips just announced two major urban farms in Japan that are using the new luminaire. The Innovatus farm in the Fuji area is producing 12,000 heads of lettuce each day using the fixtures (Fig. 6). But van der Feltz also said other growers might use the tunable product to develop optimum recipes and then deploy a mix of fixtures in fixed colors in a commercial farm.

Osram also announced a new set of horticultural fixtures in its Zelion family recently. The series includes spectrum-tunable models focused on delivering PAR light. Those Osram products also include PC software to control the fixture output.

Horticultural revolution
Ultimately, LED lighting is poised to revolutionize all types of horticulture. Consider tomatoes. In one of the earlier linked feature articles, we cover a North Carolina tomato farmer called Patterson Greenhouses that was able to significantly extend the growing season even in a relatively warm region of the globe. We also covered a Philips Lighting tomato project in France where the fruit is apparently tastier under LEDs (Fig. 7). That project used the aforementioned interlighting with LED luminaires from Philips that you can see in the photo running horizontally between plants.

Of course, taste will always be a qualitative issue. The Stockbridge Technology Centre in the UK is an industry- and government- funded research organization working in horticulture and has done significant tomato research. Applied photobiologist Phillip Davis discussed the organization's work with tomatoes and said they tested tomatoes in four lighting scenarios - HPS lighting from above, HPS from above with LED interlighting, LED from above, and LED from above with LED interlighting. Davis said yields were similar but that test subjects preferred the tomatoes exposed to interlighting in both cases.

Indeed, interlighting can change the way tomatoes are grown. Stockbridge lets the plant grow to heights not typically practical for maintenance, harvesting, or lighting. But interlighting continues to supply energy to the lower foliage and harvesting occurs invariably in the lower portion of the plant. As a 1-2-ft section of the plant exhausts its productivity, the Stockbridge team lowers the plant that is tethered vertically such that the fallow stalk is parallel to the ground but still supplying nutrients to the rest of the plant, bringing the next section of the plant into easily harvestable reach. The technique produces tasty fruit and extends the productive life of the plant.

The impact of LEDs will still likely be of a larger magnitude in vertical farms, and will change completely the way farmers do business. Green Sense, for example, doesn't plant a head of lettuce or a basil plant until it has an order for that plant and a promised delivery date. The precisely-controlled growing environment delivers very predictable growth cycles that are double or more the frequency of outdoor cycles. Colangelo said micro greens require 8-10 days while lettuce requires 35-40 days. Green Sense contracts with buyers for its total production in advance. About the model, Colangelo said, "It takes market risk out of farming."

Green Sense has a global vision for its business, thus its recent opening of a farm in China. Colangelo said the company would look to expand in any region where the economy will sustain a demand for a premium product and where either growing seasons are short or land and water resources are constrained. He said the Chinese population is increasingly demanding better quality products including food, and pollution in both water and land resources limits growing space, making vertical farming a great match. Colangelo has a number of other farms in the planning stage with the next up for commercial operation being another Indiana operation in conjunction with the Ivy Tech Community College in South Bend, IN.

Local Roots, meanwhile, has a different plan to serve the global market. Vail said the company's mission is "better food for the people and better practices for the environment." That mission runs through the choice of shipping containers as a growing vessel that might otherwise be thrown away to enabling urban operation near population centers. The company literally operates in the heart of downtown Los Angeles and supplies restaurants and farmers' markets in the area with just-harvested greens and herbs.

But Local Roots has a different vision for going global. The company may itself expand operations and Vail said, "We will always be farmers growing food." But the company is now moving toward selling a fully functional farm to other growers. Local Roots would completely equip a shipping container including with its own IP in light recipes and software controls, and ship the container to select growing operations. Vail said it would really be selling a farming business as opposed to selling equipment.

Of course, the question remains as to why ship an extremely heavy container pre-equipped with LED lighting, drivers, pumps, computers, and more as opposed to just supplying the equipment. Vail said it goes to repeatability and the proven form factor along with Local Roots' ability to assist potential customers with what is a precisely known environment. Vail said the company has yet to sell such a farm but has had hundreds of growers approach them on the topic and is active in discussions with dozens of groups.

Without question, LED lighting is not for every type of horticulture. It would be hard to imagine anything replacing Vidalia onions grown in a specific type of soil in southeastern Georgia, or watermelons from Texas, and more. But if LEDs can enable tasty tomatoes year round, and enable access to pesticide-free greens that don't even need to be washed, such a scenario would be a great step forward.

There are, of course, other issues to be solved. Fungus can be an issue indoors with no UV exposure. Plant circadian rhythm is still not well known. But new LED technology could come to play in those areas also. Indeed, that topic will be the focus of the Closing Plenary at our aforementioned Horticultural Lighting Conference, based on research done by Jaimin Patel and Mark Rea of the Lighting Research Center at Rensselaer Polytechnic Institute, and David Gadoury of Cornell University.




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BombBP

BombBP

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Nice read but does anyone get the feeling these scientists are just watching the weed growers use LEDs?
 
Wee Zard

Wee Zard

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That's exactly what many of them did.
I started using leds in '06 and a bunch of us figured things out together by sharing our methods and observations in a public forum.
It did not go unnoticed by people looking for products to market. :)

Aloha,
Weeze
 
jumpincactus

jumpincactus

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Personally, as I haven't migrated yet to LED/SSL tech am still reading between the lines , every paper and study I am seeing is still based on growth rates and color matrix recipes for low light leafy green. Basically plants that dont rely on deep canopy penetration such as cannabis.

I to this day, believe that any manufacturer that is touting LED for cannabis is really just throwing lights together and with the promise of lower temps and less hvac cost and are allowing us , we the growers to figure out what works. Sort of beta testing, until such time that we get verifiable continuous grows and data as to what works best.

I will say this, anything built using COB's seems to be smashing it, in as much as LED's go. But I'm still not quite there due to yeilds compared to MH/HPS watt for watt just arent there yet.

Ya I know there are all kinds of claims and youtube video's that make bold claims as rivaling HID but I still am reserved and holding to HID until the sector can bring affordable, reliable lights that can produce the yields of legacy lighting systems. However, I don't think that day is far away.
 
Wee Zard

Wee Zard

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QUOTE="jumpincactus, post: 1873619, member: 30034"]I to this day, believe that any manufacturer that is touting LED for cannabis is really just throwing lights together and with the promise of lower temps and less hvac cost and are allowing us , we the growers to figure out what works.[/QUOTE]

Change that "any" to most, and I have to agree with you.
And different "strains" respond differently depending on the R:B ratio. I use adjustable ratios and "tune" the lighting to the kine.

While it is true that I get roughly 10% less weight per plant with LEDs vs HPS.
It is also true that I'm doing that with lass than half the power cost. :)
And the quality, taste, and potency are as good and better. (Some "strains" do not do well under any artificial light. :(
But some do better under leds than they do in Hawaiian sunlight.
led front sun backJPG.jpg

Led lady in front sun girls in back
led sun led G13.JPG

Sun grown is in the middle, with a bigger pot.
Led grown on the ends. They can use a smaller pot because transpiration is about half what a sun grown plant does.

Yeah, I know, surprised the shit out of me.


Aloha,
Weeze
 
AvidLerner

AvidLerner

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light source is closer with led vs, sun. higher ppfd in confined space unlike sunlight. take par readings at both locations and that may surprise you. nice grow btw. great looking ladies, well cared for.
 
jumpincactus

jumpincactus

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QUOTE="jumpincactus, post: 1873619, member: 30034"]I to this day, believe that any manufacturer that is touting LED for cannabis is really just throwing lights together and with the promise of lower temps and less hvac cost and are allowing us , we the growers to figure out what works.

Change that "any" to most, and I have to agree with you.
And different "strains" respond differently depending on the R:B ratio. I use adjustable ratios and "tune" the lighting to the kine.

While it is true that I get roughly 10% less weight per plant with LEDs vs HPS.
It is also true that I'm doing that with lass than half the power cost. :)
And the quality, taste, and potency are as good and better. (Some "strains" do not do well under any artificial light. :(
But some do better under leds than they do in Hawaiian sunlight.
View attachment 676738
Led lady in front sun girls in back
View attachment 676739
Sun grown is in the middle, with a bigger pot.
Led grown on the ends. They can use a smaller pot because transpiration is about half what a sun grown plant does.

Yeah, I know, surprised the shit out of me.


Aloha,
Weeze
[/QUOTE]
Dang Weez, very respectable. I appreciate you sharing that with me. Please don;t get me wrong I sincerely believe the day will come when LED will be the preferred method, just for the cooling and cost savings for starters.
So did you say the LED grown have good thrich and terpene profiles as compared to sun grown? I find that interesting, considering your location as well. Peace
 
Wee Zard

Wee Zard

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So did you say the LED grown have good thrich and terpene profiles as compared to sun grown? I find that interesting, considering your location

I did say that.
Got choke pictures from when I was piddling around with UV b and c.

Found that the UV in tropical sunlight drys, and fries, the glands.
Causes them to rapidly shrivel and drop off as tiny black dots shortly after they go amber.
kept seeing empty trichs.
So I waited for a windless day, turned off the fan, and laid paper sheets on the soil surface.
Found tiny, (almost invisible), black shriveled up capitate glands.
Did not collect enough to try them for potency, but I'm guessing they are mostly CBN by then.

When clear, the light goes right through the glands, but, as they ripen, light is occluded and becomes heat.
It's a runaway process, the darker they get, the faster they fry.

LEDs have 0 UV so there is no attrition. The buds just keep popping more glands until it's a solid carpet.
red hair 2.jpg

PIC044.jpg

And it turns out that UV is not needed to create our favorite cannabinoids.
The 660nm. red does that.


And the lack of radiated IR keeps the terpenes from "boiling off."
So led grown buds are very aromatic.
amber.jpg

Note the headless trichs, and less glands of sun grown buds.


Ya see, I'm not a believer. Or a bandwagon rider.
I investigate everything that I can, as deeply as I'm able.
Mostly because I'm on a fixed income and can not afford to make mistakes.

Without LEDs, It would cost me more to grow, than to buy.
We get deeply gouged by the power company. ~ $ .40 per kWh.
If LEDs didn't give me very potent, and tasty bud, I would dump them in a New York minute. :)

Aloha,
Weeze
 
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lino

lino

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I did test with Gamma, LED, i was calling em diodes on threads back then (we hadnt came up with a good name yet in growing so growers went with the electricians name LED), CFL and Argon and some other lights,,, ppl laughed me off this site... not so funny anymore. there are many lights that have not been tested. IMO most of these lites -they all give VERY WEIRD growth.. I took care of garden last week -Got 12"-15" leaves on 2.5' plant with LED's WTF... There are lots of lights out there to still be tested. we hav no idea about lighting yet.... Last wk I saw a student stacking on trich like a mo fo with some high intensities lazors, crazy shit, he got all secret on me when I him asked some questions,, blending lazor lites and crazy shit.. so much we dont know about light.

Simple light tool that spins when lite hits hits it.. Look at the Crooks Radiometer, built in the 1800's and no one can explain how it works. Last mth the bald headed magnet guy came out with some nice theories after hitting it with some lazors... Lazors are turning out to be the shit, Zero wasted light, can be programmed to hit the plant only

I still say,,, nothing can beat the cost of free Sun watts. and optimum lighting will be a combination of lights . But the say the Lazors can do it all and best replicate the sun at the least amt of cost,,, we'll see?


@Wee Zard
Your neighbors are pleased with your aesthetically pleasing bamboo fence. But go get a skunk farm permit from your city just in case any neighbors complain about the skunk smell in your hood...
 
jumpincactus

jumpincactus

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Wow thanks Weeze. Very nice detailed findings. Good to see folks living outside the box!!! Damn dude I realize your on an island but gimminy xmas they are bending you folks over over that side of the pond!!! Geeesssh Sad part of that reality is this, it is the average joe citizen paying those rates and the big corps and hotels and the tourism industry get massive breaks on their rates based on usage. What a friggn scam. So it us little guys that bear the brunt of the profit margins, bonuses and bottom lines. :(
 
Wee Zard

Wee Zard

495
143
View attachment 677404
Simple light tool that spins when lite hits

You mean this guy?
DSCF6293.JPG


It's called a radiometer and we do know how it works. :)

I used one to test my arrays.
Because meters measure white light, and I needed to find out how close I could hang my lights.
I note the speed in sunlight, then adjust the LED's distance until it's about the same speed.
Kept me from getting light bleach.
Then I adjust the R:B ratio until the leaves look black.
That get me maximum absorption.
Yeah, I know, it's not "science" but it works. :)


PS
I did futz with lasers a bit, just because I could.
Managed to raster scan a whole leaf, but it was not easy.
Bottom line?
No matter how you slice it, 5 mW. won't grow a bush. :D

Aloha,
Weeze
 
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lino

lino

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View attachment 677404


You mean this guy?
View attachment 677413
I used one to test my arrays.
Because meters measure white light, and I needed to find out how close I could hang my lights.
I note the speed in sunlight, then adjust the LED's distance until it's about the same speed.
Kept me from getting light bleach.
Then I adjust the R:B ratio until the leaves look black.
That get me maximum absorption.
Yeah, I know, it's not "science" but it works. :)
that Kinda what we speculated until recently... Lazor lite killed all the theories about the Crooks. Nobody knows what the hell makes it spin. But the Magnet Guy is on to something with his Demo,,, his been showing off at universities. on my thread seed 2 seed.

some lazors with wht lite dont move the crooks... everyones baffled . IMO/guess Magnet Guy theory is close.
 
Wee Zard

Wee Zard

495
143
Your neighbors are pleased with your aesthetically pleasing bamboo fence. But go get a skunk farm permit from your city just in case any neighbors complain about the skunk smell in your hood...

If he no like? Jus' fine by me.
I have a rec. and I abide by the rules.
He tries to grow, but will not read a book. So he ends up ranching spider mites on his hermies. :D
He's a bit of an idiot and is growing without a blue card.

I am more annoyed by his night gardening with a 150W. incandescent floodlight on his flowering gals.
That's what the bamboo fence is for.
What a maroon!

I have to deal with his hermie pollen and wind born bugs.

And I love the smell of skunk, in the morning it smells like, Victory! :)

Aloha,
Weeze
 
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Wee Zard

Wee Zard

495
143
everyones baffled

Not everyone.
some lazors with wht lite dont move the crooks...

Perhaps these "lazors" you speak of do not spin a radiometer.
But there is no such thing as a "wht lite" L.A.S.E.R.
Light Amplification by Stimulated Emission of Radiation
It is, by definition, a very narrow bandwidth coherent light.
And if you would like to know how a radiometer works. I'd be happy to explain it to you.
But mo' betta, look it up. No wanna hijack a thread.
And most of what I know was stumbled over while searching for something else. :)
 
AvidLerner

AvidLerner

296
63
I use Deep red 630nm Far red 660nm and IR in the lights I build for flower. I would agree with trich development it is a combination of these colors more than UV.
 
Wee Zard

Wee Zard

495
143
Must be typos.
Your ppfd comment was spot on.


635s are a little orangish, yah?.
660s are deep red.
720 -770 are far red.
The far red is useful for re-setting phytochrome if applied for an hour at lights out.
I have found nothing useful in IR unless I want some stretch.
 
Major91

Major91

51
33
5x5x8 indoor grow with MarsHydro300 cheapo in soil week 6 of flower...........I may try HPS/MH or Cobs down the road but my Led's are kickin it........to my likings.....
 
jumpincactus

jumpincactus

Premium Member
Supporter
11,613
438
View attachment 677404


You mean this guy?
View attachment 677413

It's called a radiometer and we do know how it works. :)

I used one to test my arrays.
Because meters measure white light, and I needed to find out how close I could hang my lights.
I note the speed in sunlight, then adjust the LED's distance until it's about the same speed.
Kept me from getting light bleach.
Then I adjust the R:B ratio until the leaves look black.
That get me maximum absorption.
Yeah, I know, it's not "science" but it works. :)


PS
I did futz with lasers a bit, just because I could.
Managed to raster scan a whole leaf, but it was not easy.
Bottom line?
No matter how you slice it, 5 mW. won't grow a bush. :D

Aloha,
Weeze

ˈmäˌhälō my friend. Sounds like science to me. :cool:
 
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