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HPS vs LED Grow Lights: The Spectrum Efficiency Showdown

Are you interested in the science behind spectrum?

How plants see light?

Check out our blog post exploring the affects of spectrum on plant growth here:


@thegreensunshineco, which do you prefer – HPS pr LED?

Can someone here offer a strong position of why all growers should not switch to LED?


@Growernick ROI and lower energy costs, ability to adjust spectrum. In 2 years, it’ll be a question of “why are you going with HID”. LED gets better and better as time goes on.


I agree with this position!


I was mentioning that the R+D market in LED technology is jumping heavily. Seeing low end producers even stepping it up!:cowboy_hat_face:


When the Dutch convert to LEDs I’ll think about it. I know Gavita makes LEDs but it’s not the industry standard. If you want to grow like the best…grow like the best.

How about light emitting plasma? Gram per watt is reported to be on par with double ended.

LED might be the future but it’s not the standard at this time. I think growing in warehouses is weird anyhow and the future is Controlled Environment Greenhouses. Completely sealed co2 enriched stable RH temps complete with light dep sensors of all types communicating with on the fly analysis and dosers that can micro manage every element the plant needs. The light discussion is tired and environment management is where it’s at.


I have yet to be fooled in person by a flower grown by Led compared to a flower grown by HID’s or LEC’s. I have found that LED grown flower never has the density that I prefer. LEC and HID are extremely close in terms of flower density and every other factor. I find it’s because most LED’s never get that light penetration through the canopy. Also I am not hearing of people pulling 2 to 3lbs per light regularly if ever on LED’s as I am with HID’s and LEC’s


We would all love to grow in Greenhouses in completely controlled environments but because of the draconian US cannabis growing laws in a lot of places outdoor and or greenhouses are outlawed. Still crazy in a place like California do we let individual municipalities decide there own rules. The state of California voted as a State together to legalize cannabis now they let cities decide if to allow cannabis and in what forms are legal to them. It should be ILLEGAL for cities to ban cannabis or regulate it. If its going to be regulated which i’m against it should be regulated statewide.


Right? I have never had the filling out, like I did with HID lighting. My success is in using both. I run my CMH halfway through flower, then switch over. I change the spectrum according to natural cycle. I get the heavy icing from LED, but density shows through on HID lighting.

LEDs are great and all, but the more i look into them, they are going to be obsolete with the way CoBs are coming around.:cowboy_hat_face:


Cobb is the way to go for sure. There so much cheaper, brighter and denser with there output.


Plus from my understanding it is pretty easy to just build yourself a cob lighting system out of multiple cob’s and chips.


Agree on many points, HID creates the widest spectrum. If power was unlimited and free, those would win any day of the week. There would be almost no reason to go with LED, except in a select few situations.

Areas where LED is more desirable:

  • Double Stack Setups
  • Low Ceiling Setups (Where only SE bulbs are possible)
  • Home Grows / Tents (No need for A/C or heat issues)

LED systems are not all created equal, and there is no standard between spectrum, intensity, spread pattern, etc so one grower’s experience will differ from another since “LED” is not the same as “LED”. The fact that the first LED manufacturers basically lied about wattage and efficiency has not helped the industry’s reputation.

What the market is full of now are “white” LEDs (which lack far red/infrared), which will grow entirely different than HID bulbs, especially moving from strain to strain. Since the heat signature is also completely different, a new learning curve and growing style is required to dial in environment, nutrients, etc. Additionally, strains that have been bred to yield under HID may not perform as well under LED, so there is that to consider.

COBs are great, however the highest efficiency diodes on the market are the small “mid power” diodes that are tiny squares. Currently white (blue coated) LEDs are at a 79% efficiency level, with a theoretical maximum of 90%.

At this point, HID is a surefire guarantee, LED is an early adopter game, there’s barely any research performed on spectrum, and it will be exciting to see what the next few years hold as cultivation is legalized and growers learn the difference from brand to brand. I’m excited to see the research that unfolds as we learn more about how plants react to light with this technology.


It is very easy to assemble your own… Heat sink, chip, driver, lense, good to go! Similar to what’s on the market, the DIY allows you to configure to your grow set up! I put mine on bars and hang aside my HIDs (CMH). Then i dont have to take down, or manually switch.

I do have to question the notion that most all production diodes and chipsets are white with an overlay. Usually, if you see an LED set with no known markings, configuration, and housing, then its an off make, which yes, likely covered. I have been on the phone more then I care to with some of these manufacturers, like Mars. Those folks are mad, lol! I like to test many lights, and get to the bottom of them as i get a ton of questions daily from new growers asking “What light is the best?” and lets not forget “for the price”… those two coincide with home growers alot, which will be a very heavy demanding market. I check PAR, get spectrum results, and then test energy efficiency. This initially stemmed with our interest to operate indoors, off grid. I have tested a wide variety of lights for a lot of strange things for folks, and have been seeing the market change for more correct spectrum needs. I hope that helps!:cowboy_hat_face:


We have found that Chip On Board (COB) LEDs have not been keeping up with the advances in efficiency with other types of LED packages such as 3030 midpower white LEDs and multi-die 5050 LEDs in the last 12-18 months. On the LED chip/package supplier side of the industry, most are in agreement with this position as evidenced by the recent Horticulture Lighting Conference last month in Portland OR, which was attended by all of the major LED manufacturers such as Samsung, Nichia, Osram, Luminus, Cree, and others.


Maybe HPS bulbs will be preferable in places like Alaska, where the extra heat is needed. Here in Florida, its the exact oposite.


Good point! I often view thing with a set of desert lenses since we’re constantly being roasted by the sun here in Too Stoned, Arizona! LED definitely is preferable down here…


This has always been a strange topic of debate for me…We should not be seeking less efficient lighting systems, simply because they produce more heat, which is due to their inefficiency. It simply does not make sense. If you need more heat, heat your space…Why would one consider outdated, inefficient tech, for their operation, just because it produces more heat?

Consider the totality of energy savings accompanied by incorporating a proper lighting system within your operation. Wouldn’t these savings enable you to purchase equipment to adequately control your environment, while running proper systems which don’t generate as much heat as the old tech?

Canada is cold, as we all know. Yet the big operations out there aren’t interested in HID lighting for their plans to outfit millions of sq. ft. of growing space. Why? Because they know they can control their environments without letting inefficiency heat up the space for them.


Its already a valid question. Can someone make an objective attempt to provide an answer to that question, please?

“If you’re looking to purchase a new lighting system, why would you go with HID?”

…Very interested in any response.


Please don’t cite heat. Space heaters exist.



So this is a spectruam analysis of the sun, the lights is use, and a hps name brand. note my lighting in this test is 100w less the the hps