Spectrum

Lighting spectrum (color distribution) is very important for growing plants. Even among traditional lighting technologies, low pressure sodium lights aren't used to grow plants; even though they're more efficient than high pressure sodium, they don't have a plant-growing spectrum.

Most of the LED companies out there agree that some colors are more useful to plants than others, and many even claim that light outside of the visible range is good for growing plants. Scientific research has shown that plants primarily use colors in the visible range for photosynthesis, but that plants are also affected by light outside the visible range. Scientific research also demonstrates that the ratio (relative intensity) of different colors of light has important effects on plants.

It would be awesome if all LED vendors would list the LED wavelengths they use as well as the ratio, but at the moment this information seems to be considered something of a "special sauce" and isn't commonly shared. Some companies do give a graphical representation of their lights' spectrum, which is very useful (if it is real – some of the spectrum graphs aren't accurate).

In my opinion, the best LED grow lights have a spectrum which incorporate all of the wavelengths plants need for healthy growth, including UV and IR, and don't use mainly "white" LEDs. I know not everyone will agree with me about this, but see below for the details of my reasoning. The companies who have at least one light model that meets all of these criteria are listed in "All / Some Good" column of the table above, companies lying about their spectrum in one way or another are in the "Liars" column, and everyone else is in "The Questionable" column.

You can see all of the spectrum data for each model light in the table at the bottom of this page.

Ads by Google
Why are there ads on this site?

Questionable Claims

There are a few things I noticed in my research that are worth noting:

Lying by Omission?

Truth Lighting says they are Dedicated to supplying indoor growers with factual data on our actual spectrum, Truth Lighting is one of the only suppliers performing after-factory quality control on its LEDs using a professional grade spectrophotometer. Yet they don't supply any information I can find on their actual spectrum or a spectrum graph! They have replaceable modules in their lights so you can choose from "Full Spectrum", "Heavy IR/White", "Heavy Red", "Veg/Heavy UV" and &qupt;10K/Veg&qupt; modules — but as far as any actual information (beyond the name of these modules) about what spectra are in them, they provide none at all. With no information at all about what you are or aren't going to get, I wouldn't recommend buying a light from them.

Stretching the Truth?

Lush Lighting claims their light is Full Spectrum, UV to IR, and previously said Lush Lighting's products produce the most energetic photons plant's can absorb, UV light! Intense enough to turn green twist tie blue in only weeks. The twist tie discoloration method of measuring UV light seems a little suspect and not terribly scientific; I've had twist ties that change color with exposure to water. They provide no spectrum graph and they do not claim to have any actual UV LEDs (those with a peak wavelength of 10-400nm) in their light. Do they really have UV?

Kind LED also claims to have UV in their spectrum and they explicitly say that their lights include both infrared and ultra violet diodes, and the spectrum graph they provide does show light down to about 370nm. But, their spectrum graph is clipped (see below) so cannot be trusted.

Clipped Spectrum Graphs

Many LED companies have graphs showing their lights' spectrum, but a lot of these graphs are clearly wrong and are "clipped".

LED diodes naturally give off slightly different colors of light on either side of their "peak" wavelength, in what is called a "normal" distribution also sometimes called a "bell curve" as it is shaped like a bell. LEDs coated with phosphors ("white" or "full-spectrum" LEDs) still have this natural "rounded" spectrum but with multiple "humps"- one for the underlying LED's, and one for the phosphors'. So when LED grow light companies post spectrums with "sharp corners" in them, it seems very fishy– there is almost no way to make a spectrum look like that with LEDs. Other methods of creating light such as discharge tubes (HID lights) can have "spikey" spectrums because of the different way they create light, but LEDs don't.

Incorrectly using a spectroradiometer (or not using the right one) will result in the sensor being overwhelmed, causing the resulting spectrum graph to be "clipped" and incorrect.

Advanced LED, Kind LED, Platinum LED and Spectrum King all have spectrum graphs on their websites which are clearly clipped and are not showing their actual spectrum. For companies claiming to be lighting and spectrum experts, this seems to show that they either have no idea what they are doing — or perhaps they are using these clipped graphs because they make it look like their light more-evenly covers the spectrum than it really does. Interestingly, all 4 companies show that they are (mis-)using the same UPRTek spectroradiometer, which isn't designed to handle bright lights. So much for these companies being lighting spectrum experts!

Pro Max Grow provides a spectrum graph with 2 unlabeled curves on it. Which is their spectrum? One curve is from ~380nm-770nm, the other from ~460nm-780nm. Perhaps we're meant to mentally add the two lines, but if so shouldn't they cover the same range? This isn't a real spectrum graph at all- they are just putting together a pretty graphic to try and sucker people into buying their extremely overpriced lights.

Spectrum Band Graph

While the number of different LED colors included in a grow light isn't the only thing you need to look at for determining if a spectrum is good, it is the only thing I can effectively put in a graph of this type.

Loading graph…

Ultraviolet (UV)

Based on my experience, I believe that UV light is important to include in an LED grow light spectrum. HPS has no UV, so you may not even realize what you're missing until you have grown with UV– it just seems to increase bud quality when you have it, and certainly increases pigmentation. One of the advantages LED lights have over traditional HID lighting is the ability to fine-tune the spectrum to anything you want, so I see no reason not to have UV to increase quality.

UVA vs. UVB

California Light Works' Solar Storm series are the only lights I'm comparing here that include UVB in their spectrum. They achieve this by adding fluorescent UVB bulbs (commonly called reptile bulbs) to their LED fixture. They claim UVB is important because The sun naturally contains large amounts of UVB. I think this is quite misleading because sunlight has a maximum of 0.15% (about 1/6th of 1%) of UVB; I don't consider that a "large amount". In comparison, 2.85% or more of the sunlight that gets through the atmosphere is UVA– 19 times more than UVB.

At least one plant pigment has been identified which reacts to UVB light and initiates the plant's stress response, so UVB light does trigger something in plants. However, it is unclear whether this is needed (instead of UVA) to get optimal growth or quality from your plants.

In my own past tests growing with fluorescent UV sources ("black lights" for UVA, and "reptile bulbs" which have some UVB), both kinds of UV did seem to make the plants more resinous than without UV. Plants grown under UVB seemed more stressed and damaged though, so I didn't see any benefit in using UVB instead of UVA. But, my tests were hardly scientific so all I can really say is that UVA worked better than UVB for me.

I can also say that UVB is far more harmful to your health than UVA, so you may want to wear sunscreen and UV-blocking glasses when working with your plants while the UVB is on. And, if you do decide to experiment with UVB for yourself, there are better, cheaper ways of doing it than buying an LED light with added UVB fluorescent bulbs.

UV Lies

Spectrum King claims their lights consistently produce spectrums from 380-779nm, thus claiming to have ultraviolet in their spectrum (below 400nm). This statement is carefully worded to be technically correct but highly misleading– they have no meaningful UV in their spectrum at all. All "bare" LEDs without phosphor coatings produce photons in a normal distribution, meaning the vast majority of photons are produced within a 20-50nm of the LED's "peak wavelength". Some photons are still produced outside of this range; the further you get from the peak wavelength, the less are produced. Standard blue LEDs (including the "white" phosphor-coated blue CREE LEDs Spectrum King is using) will occasionally produce photons in the UV range, so they are technically correct. However, this UV output is less than 1/10th of 1% of their lights' output and is insignificant to your plants.

It is equally technically correct to say their light fixture is radioactive. Everything you deal with daily has a low level of radioactivity– even air, and there's air in the Spectrum King light. While this radioactivity is measureable, it is insignificant, just like the UV content of their light. So in the same way Spectrum King would probably (and rightfully so) call me a liar for saying their light is radioactive, I'm saying they're lying about having UV.

Infrared (IR)

Since 1957, science has known that giving plants near-infrared light (700 to 740nm, at least) actually increases the efficiency of photosynthesis due to the Emerson Effect. Plants will grow without near-infrared light, but since it increases photosynthetic efficiency, it seems silly not to have some in your spectrum.

White Dominant

As prices of white LEDs have dropped dramatically in the past few years– they are now cheaper than specific-color LEDs– there are more and more grow lights on the market which are composed mainly of white LEDs. Some vendors argue that their all-white LED grow lights are better than those using specific-wavelength LEDs.

I suspect the recent increase in all-white LED grow lights has more to do with the cheaper price of white LEDs than the quality of the growth under these lights. These so-called "white", "broad spectrum", "full spectrum" or "high CRI" white LEDs employ a special coating of phosphors to turn some or most of a blue LED's light into other colorsmostly yellow. White LEDs are designed for humans and provide a high lumen reading that our eyes are most-sensitive to, but which plants don't need a lot of. The general spectrum of white LEDs doesn't compare well to the chlorophyll absorbance spectrum.

The white LEDs are also 20-40% less efficient than single-color LEDs because of how they make white light with phosphors. This is fine when it's 10 or 20 watts of light in your kitchen, but the inefficiency really starts adding up when you're running hundreds of watts of LEDs in one fixture.

Including some white LEDs in a plant grow light probably makes sense, even if it is just to help you see the plants better. Even companies that use a large number of different-color LEDs include some white LEDs in their spectrum, as these help ensure some coverage of most of the visible wavelengths.

But because of the human-optimized (and not plant-optimized) spectrum and inefficiency of white LEDs, having 50% or more of your LED light in the form of white LEDs seems like you're missing out on the promise of an efficient and ideal plant spectrum. You may or may not agree, but I'd recommend a careful look at grow results from lights composed of 50% or more white LEDs.

Minimal Spectrum

Most people have heard that plants need blue light for vegetative growth and red light for flowering. It's true that plants don't veg well without enough blue and they don't flower well without enough red. From personal experience, I'm convinced that changing the color of your light from veg to flower is a bad thing if your light has enough blue and red to begin with, but I know some people might disagree with me. Still, scientific research has shown that both blue and red light are used by plants for hormonal signaling for growth regulation.

Despite this, some LED vendors have taken things to the extreme and offer all-blue veg lights, and all-red flowering lights. The all-red lights I compare here are marketed strictly as supplemental lights by all vendors that offer them, and they may be ok as a supplement to another light. Still, why buy 2 lights when you can buy 1 that does it all?

Advanced LED's Diamond Series EX-Veg lights are marketed as sole sources of light, but are only blue. While some plants will grow under all-blue lights, they won't grow as well as with a more balanced spectrum, and will undergo extreme shock when moved to a full-spectrum light, stalling out for many days while they get used to better light. If you don't believe me, by all means try it out yourself in a side-by-side test with a better-spectrum light– any plant that grows stems (i.e. not lettuce) will show the effect. If you're looking at buying one of these all-blue lights for supplementing an HPS for veg or flower, they may work well for that purpose, but as a sole source of light I'd never recommend them.

Several years ago, there were many LED lights on the market composed of just red and blue LEDs– 2 different color bands.

Apache Tech is the only company I'm reviewing that still offers lights with just one red and one blue color in their AT120RB model. While plants will grow under these lights, there's a reason the other LED vendors I'm comparing throw in other colors, even if it's just some white LEDs. Again, one of the advantages to LED lights is that you can customize the spectrum to try and excite all of the light-absorbing compounds in plants, and settling on just one red and one blue is really selling yourself short.


UVB Footnote

3% of the sunlight that makes it through our atmosphere is UV, when the sun is directly overhead in the sky. At least 95% of this is UVA, meaning that (95% of 3% = ) 2.85% of sunlight is UVA. At most, 5% of the UV light is UVB, meaning that at most (5% of 3% = ) 0.15% of sunlight is UVB. The amount of UVB that actually makes it through the atmosphere is highly dependent on cloud cover and atmospheric conditions, so UVB is usually less than 0.15% of sunlight.

California Lightworks and Hydro Grow both point to a 1987 study suggesting that only UVB light affects THC production in Cannabis Plants, but a later study showed the cellulose acetate filter used in the first study let UVB and UVA light through. Given the newer evidence, the only conclusions that can be drawn from the 1987 study are that Cannabis plants produce higher THC when exposed to a combination of UVA and UVB- but it cannot narrow down which wavelengths are responsible.


Spectrum Data for All Lights

In the table below, "?" entries in the "Actually have UV" column mean that I haven't been able to independently verify whether the lights actually include the UV they claim– yet. I just received an awesome StellarNet spectrometer which will allow me to test LEDs for spectrum claims, including UV, so if / when I get access to a light I'll now be able to verify claims. Check back soon as this column will be getting updated!

The data table is very large- you may need to scroll side-to-side as well as up and down to see the whole thing. Larger screens help! If you're only looking for one company or light model, enter the name in the search to only show those results.

CompanyConclusion RankingProductLight TypeClaim UVHave UVActually have UVIR>50% "White"50% or More "White" DiodesClaimed Wavelengths# Colors# of Different LED Colors
Diamond Series DS 100 - Extreme 3w
Yes
?
Yes
380-760
11
Diamond Series DS 200 - Extreme 3w
Yes
?
Yes
380-760
11
Diamond Series DS 300 - Extreme 3w
Yes
?
Yes
380-760
11
Diamond Series DS 400 - Extreme 3w
Yes
?
Yes
380-760
11
Diamond Series DS 600 - Extreme 3w
Yes
?
Yes
380-760
11
Diamond Series DS 800 - Extreme 3w
Yes
?
Yes
380-760
11
XTE Series DS XTE 100 - 5W LEDs
No
N/A
Yes
410-760
11
XTE Series DS XTE 200 - 5W LEDs
No
N/A
Yes
410-760
11
XTE Series DS XTE 300 - 5W LEDs
No
N/A
Yes
410-760
11
XTE Series DS XTE 400 - 5W LEDs
No
N/A
Yes
410-760
11
Diamond Series EX-Veg DS200
No
N/A
No
410-510
1
Diamond Series EX-Veg DS300
No
N/A
No
410-510
1
Diamond Series XML DS XML 150
Yes
?
Yes
380-760
11
Diamond Series XML DS XML 350
Yes
?
Yes
380-760
11
Diamond Series XML DS XML 650
Yes
?
Yes
380-760
11
AT-120WB (White and Blue LEDs)
No
N/A
No
Yes
400-650
2
AT120RB (Red and Blue LEDs)
No
N/A
No
425-670
2
AT120W (All white LEDs)
No
N/A
Yes
Yes
400-750
1
AT120WR (White and Red LEDs)
No
N/A
Yes
Yes
400-750
2
AT-600-WR2 (White and Red)
No
N/A
Yes
Yes
400-750
2
GL100LED Full Spectrum 300W LED
No
N/A
Yes
?
430-730
?
GL80x5LED Full Spectrum 400W LED
No
N/A
Yes
430-730
6
Full Spectrum 600 Watt LED
No
N/A
Yes
430-730
6
GL140x5LED Full Spectrum 700W LED
No
N/A
Yes
430-730
6
Full Spectrum 900 Watt LED
No
N/A
Yes
430-730
6
Full Spectrum 1200 Watt LED
No
N/A
Yes
430-730
6
GL25LED Full Spectrum 75W LED
No
N/A
Yes
460-730
4
GL25LED Full Spectrum 135W LED
No
N/A
Yes
460-730
4
GL25LED Full Spectrum 180W LED
No
N/A
Yes
430-730
6
W90-3000K
No
N/A
No
Yes
white
1
W90-4000K
No
N/A
No
Yes
white
1
W90-5000K
No
N/A
No
Yes
white
1
PhytoMAX 200
Yes
Yes
Yes
365-750
13
PhytoMAX 400
Yes
Yes
Yes
365-750
13
PhytoMAX 600
Yes
Yes
Yes
365-750
13
PhytoMAX 800
Yes
Yes
Yes
365-750
13
PhytoMAX 1000
Yes
Yes
Yes
365-750
13
SPYDR 600 START-MAX Spectrum
No
N/A
No
450-660
5
SPYDR 600 GROW-MAX Spectrum
No
N/A
No
450-660
4
SPYDR 1000 GROW-MAX Spectrum
No
N/A
No
450-660
4
SPYDR 1200 GROW-MAX Spectrum
No
N/A
No
450-660
4
Solar Storm 880W
Yes
Yes
No
285-665
6
Solar Storm 440W
Yes
Yes
No
285-665
6
Solar Flare 220W LED VegMaster
No
N/A
No
440-665
5
Solar Flare 220W LED BloomBooster
No
N/A
No
440-665
5
Solar Flare 220W LED FullCycle
No
N/A
No
440-665
5
Solar Flare 110W LED VegMaster
No
N/A
No
440-665
5
Solar Flare 110W LED BloomBooster
No
N/A
No
440-665
5
90 Watt LED All RED G8 Flowering BOOST
No
N/A
No
red
?
240 Watt Full Spectrum G8LED BLOOM only
Yes
?
No
UV, Red
8
450 Watt Full Spectrum G8LED BLOOM only
Yes
?
No
UV, Red
8
240 Watt Full Spectrum G8LED Grow Light
Yes
?
Yes
UV, IR, white
8
450 Watt Full Spectrum G8LED Grow Light
Yes
?
Yes
UV, IR, white
8
600 Watt Full Spectrum G8LED Grow Light
Yes
?
Yes
UV, IR, white
8
900 Watt Full Spectrum G8LED Grow Light
Yes
?
Yes
UV, IR, white
8
E60
No
N/A
No
450-660
3
RX30
Yes
?
Yes
380-735
9
L4A Series 10 (refurbished)
No
N/A
Yes
400-735
7
LX601 C-plate
No
N/A
Yes
450-735
4
LX601 G-plate
No
N/A
No
450-660
3
LX602
No
N/A
No
450-660
3
21X-PRO 36W
No
N/A
Yes
440-740
6
84X-PRO 120W
No
N/A
Yes
440-740
6
126X-PRO 200W
No
N/A
Yes
440-740
6
168X-PRO 270W
No
N/A
Yes
440-740
6
189X-PRO 290W
No
N/A
Yes
440-740
6
336X-PRO 500W
No
N/A
Yes
440-740
6
420X-PRO 600W
No
N/A
Yes
440-740
6
Sol 1 (45 Watt Configuration)
No
N/A
Yes
440-740
6
Sol 1 (85 Watt Configuration)
No
N/A
Yes
440-740
5
Sol 2 (45 Watt Configuration)
No
N/A
Yes
440-740
5
Sol 2 (85 Watt Configuration)
No
N/A
Yes
440-740
5
Sol 4 (45 Watt Configuration)
No
N/A
Yes
440-740
5
Sol 4 (85 Watt Configuration)
No
N/A
Yes
440-740
5
Sol 6 (45 Watt Configuration)
No
N/A
Yes
440-740
5
Sol 6 (85 Watt Configuration)
No
N/A
Yes
440-740
5
Sol 9 (45 Watt Configuration)
No
N/A
Yes
440-740
5
Sol 9 (85 Watt Configuration)
No
N/A
Yes
440-740
5
NeoSol DS
No
N/A
No
400-700
?
NeoSol NS
No
N/A
No
400-700
?
NeoSol LS
No
N/A
No
400-700
?
H380
Yes
Yes
No
380-700
?
H350 (Magenta or Purple models)
No
N/A
No
400-700
4 or 5
H150 (Magenta or Purple models)
No
N/A
No
400-700
4 or 5
H150 Blue
No
N/A
No
400-500
?
H150 Red
No
N/A
No
600-700
?
K3 - L300
Yes
?
Yes
380-740
12
K3 - L450
Yes
?
Yes
380-740
12
K3 - L600
Yes
?
Yes
380-740
12
K3 VEG L600
Yes
?
Yes
380-740
12
K5 - XL750
Yes
?
Yes
380-740
12
K5 - XL1000
Yes
?
Yes
380-740
12
90 watt LED Grow Light UV
Yes
?
Yes
380-730
6
90 watt LED Grow Light HO (Vegetative Model)
Yes
?
Yes
380-730
6
BlackStar 480 watt LED Grow Light HO V2.0
Yes
?
Yes
380-730
6
BlackStar 480 watt LED Grow Light UV V2.0
Yes
?
Yes
380-730
6
BlackStar 180 watt LED Grow Light HO V2.0
Yes
?
Yes
380-730
6
BlackStar 180 watt LED Grow Light UV V2.0
Yes
?
Yes
380-730
6
BlackStar 240 watt LED Grow Light HO V2.0
Yes
?
Yes
380-730
6
BlackStar 240 watt LED Grow Light UV V2.0
Yes
?
Yes
380-730
6
Lighthouse Hydro ION 8 426w FSF LED Grow Light with UVB
Yes
?
Yes
380-730
6
Lighthouse Hydro ION 8 1546w FSF LED Grow Light with UVB
Yes
?
Yes
380-730
6
BlackStar Chrome 180w LED Grow Light FSF
No
N/A
No
425-630
6
BlackStar Chrome 270w LED Grow Light FSF
No
N/A
No
425-630
6
BlackStar Chrome 405w LED Grow Light FSF
No
N/A
No
425-630
6
BlackStar Chrome 720w LED Grow Light FSF
No
N/A
No
425-630
6
BlackStar 600 watt LED Grow Light UV
Yes
?
Yes
380-730
6
BlackStar 900 watt Commercial Grade LED Grow Light UV
Yes
?
Yes
380-730
6
LumiGrow Pro 650
No
N/A
No
400-700
3
LumiGrow Pro 325
No
N/A
No
400-700
3
DOMINATOR
Yes
?
Yes
UV to IR
?
DOMINATOR XL
Yes
?
Yes
UV to IR
?
DOMINATOR 2X
Yes
?
Yes
UV to IR
?
DOMINATOR 2X XL
Yes
?
Yes
UV to IR
?
Luminator
Yes
?
Yes
UV to IR
?
Luminator 2X
Yes
?
Yes
UV to IR
?
Vegetator
Yes
?
Yes
UV to IR
?
Vegetator 2X
Yes
?
Yes
UV to IR
?
Herbalvador
Yes
?
Yes
UV to IR
?
Herbalvador 2X
Yes
?
Yes
UV to IR
?
Mars II 400w LED Grow Light
No
N/A
Yes
440-730
6
Mars II 700w LED Grow Light
No
N/A
Yes
440-730
6
Mars II 900w LED Grow Light
No
N/A
Yes
440-730
6
Mars II 1200w LED Grow Light
No
N/A
Yes
440-730
6
Mars II 1600w LED Grow Light
No
N/A
Yes
440-730
6
Reflector-48
No
N/A
Yes
440-730
6
Reflector-96
No
N/A
Yes
440-730
6
Reflector-144
No
N/A
Yes
440-730
6
Reflector-192
No
N/A
Yes
440-730
6
MarsPro 160LED Epistar-160
No
N/A
No
440-660
5
MarsPro 320LED Epistar-320
No
N/A
No
440-660
5
MarsPro Cree-128
No
N/A
No
440-660
4
MarsPro Cree-256
No
N/A
No
440-660
4
P150
Yes
?
Yes
UV to IR
12
P300
Yes
?
Yes
UV to IR
12
P450
Yes
?
Yes
UV to IR
12
P600
Yes
?
Yes
UV to IR
12
P900
Yes
?
Yes
UV to IR
12
P1200
Yes
?
Yes
UV to IR
12
P4-XML2
Yes
?
Yes
UV to IR
12
P9-XML2
Yes
?
Yes
UV to IR
12
MAX-600
No
N/A
?
Yes
white
?
MAX-1200
No
N/A
?
Yes
white
?
Illuminator 100W
No
N/A
Yes
Red, Blue, IR
5
Illuminator Jumbo 200W
No
N/A
Yes
Red, Blue, IR
5
Illuminator Commercial 400W
No
N/A
Yes
Red, Blue, IR
5
Mother Keeper 100W
No
N/A
No
Blue, Red
2
300 Series 90° reflector
Yes
Yes
Yes
380-779
?
300 Series 120° reflector
Yes
Yes
Yes
380-779
?
400 Series 60° reflector
Yes
Yes
Yes
380-779
?
400 Series 90° reflector
Yes
Yes
Yes
380-779
?
400 Series 120° reflector
Yes
Yes
Yes
380-779
?
400+ Series 60° reflector
Yes
Yes
Yes
380-779
?
400+ Series 90° reflector
Yes
Yes
Yes
380-779
?
400+ Series 120° reflector
Yes
Yes
Yes
380-779
?
M6
No
N/A
?
No
?
?
M9
No
N/A
?
No
?
?
M16
No
N/A
?
No
?
?

Comments

Leave a Reply

Your email address will not be published. Required fields are marked *