LED grow lights V’s HPS grow lights ..

Hi all,

Over the last few years we have often been asked why we do not sell LED grow lights..’Is it because they do not work? ..’or is it that we at Somerset Hydroponics Ltd are an old skool outfit and simply have not got with the LED revolution as it were?!..

Well long overdue as it is, below is our personal opinion on the LED grow light debate. Now as this is a relatively short (really ..this is short for the subject matter!) blog i will not go in-depth into specification information ..so for all those LED geeks out there that will possibly want to pull this blog apart word by word with comparative or other specification information..please remember this is a short personal opinion just to clear up some of the basics surrounding the LED V’s (HID) HPS grow light debate!!


We feel that there is still more creative marketing surrounding LED grow lights than there is either honest reviews or results by either the manufacturers or many suppliers of such grow lights,  and this is what seems to be keeping the confusing debate alive..

What is a quality LED grow light to buy?

Too many LED grow lights we have seen on the market are not even using a horticultural grade LED lamp, they can be just a cheap torch-like LED lamps that are nailed into a panel and then marketed as a grow light! As a guide we would not expect to pay less than £300.00- £400.00 for a quality 300w LED grow light, so always check for historical reviews of any LED you see for sale. As to selling them; we have yet to be impressed enough by any LED grow light to actually stock one. There are a few quality LED units that we are aware of that are produced by reputable manufacturers, but generally we have still yet to see an LED that we are so impressed with that we would supply it/them. We are sure in the future we will eventually look at stocking LED’s as many of the bonafide manufacturers are now getting somewhere towards putting a unit together with increased wattage lamps from what is generally available.


LED grow lights have a higher colour output than other forms of grow lights?

Watt for watt yes LED’s can produce a higher level of chosen colour output than other grow lights, but this is always offset by what can be a massive drop in usable light/colour to the plant (at range) as opposed to a similar wattage HID grow light (HPS & Metal Halide lamps) and so this can leave the grower requiring more than one LED unit to achieve adequate light spread and light penetration. Therefore this may increase initial cost of purchasing sufficient LED units, and then the obvious increase in power consumption cost over a single HID grow light.


LED grow lights are cooler than HID grow lights?

LED lamps do indeed emit less heat than a HPS or Metal Halide lamp, but obviously a single 2watt LED lamp ‘would’ fire cooler than say a 250watt  HPS lamp! Multiples of combined  LED lamps will again emit less heat than a similar wattage HPS lamp (and this is where some manufacturers/suppliers will use creative marketing to get your business!) ..a bank of LED’s is indeed far less likely to scorch your plants due to the above, but what many fail to mention is that the unit powering those LED lamps gets extremely hot (especially so in cheaper, poorly made LED grow lights) and so the heat produced by the LED unit as a whole can actually increase temperature in the grow room more than if you were running an HID HPS grow light, therefore you may avoid direct scorching, but may have a general temperature issue to deal with..either way too hot is too hot and your plants will suffer!


LED grow lights for vegative growth

Basically Yes! they do work as a’ low level’ vegetative or propagation grow light for any plant under 50cm tall, but a higher wattage unit or multiple units may be required for larger plants, or where plants are in such close proximity to each other that more light is required to punch through dense leaf cover. That’s it! ..Yes, they may be the ideal vegetative or propagation grow light for you, but understand an LED grow light’s limitations and create a growing area that suits LED plant growth. It is also worth experimenting with plant variety’s that may suit better to an LED grow light. There is obviously much more i could state regarding using LED as opposed to blue fluorescent (CFL, T5 Lightwaves etc etc) or Metal Halide lamps from a magnetic or digital HID grow light..but the main objective of this blog is to tackle the ‘LED V’s HPS’ grow light debate!


LED grow lights for flowering/fruiting

Right folks..this is the bit that creates most debate and we are most often asked for our opinion regarding!..

Yes, LED grow lights can be successfully used for flowering or fruiting, but for anyone who has ever used a HPS (high pressure sodium) grow light, there is usually a considerable drop-off in the yield ability of an average plant. For plants under two feet in height for example, you may have a reasonable yield, but for anything over that height LED’s just don’t have the penetration through leaf cover that an HPS lighting system will have, and so obviously this leaves a general lower yield. For many LED growers this normally means that they have to grow more plants than they were maybe happy to grow just to try and get the same yield ability of a HPS grow light plant/crop.


Our (current) conclusion 

The above factors combined with the possibility of having to purchase extra LED units to achieve a good result, generally means that a grower will have to purchase multiple quality LED units to achieve anything like the yield ability of a HPS grow light plant/crop. This will firstly increase your budget spend compared to a quality HPS lighting system, and will also increase your power consumption spend to achieve a comparable result with HPS lighting.

Yes it is obviously possible to achieve a good result from LED grow lights, but those growers that have reached they’re goal, have only done so by setting up the grow room around the use of LEDs and not simply thrown an LED unit into an area that was previously set-up around using HPS lighting. Ultimately, knowing an LED grow light’s limitations and taking the above factors into consideration, will be the only way to achieve any kind of comparable result to HPS grow lighting.


We recommend utilising air-cooled HID HPS grow lights if reducing temperature is the goal in the growing area. Or if low wattage consumption is your goal, then simply consider multiple lower wattage HPS systems.

Personally, I would challenge any (single) 300watt LED grow light to ever out perform my growing ability with either two digital 150watt HPS grow lights or one 250watt HPS lighting system’s!!

We hope the above personal article is of use to all considering switching to LED grow lights! If state of the art growing is your goal, then take a look at Gavita Plasma grow lights..but that is a subject for another day!!..

Best regards..Lee


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