It all started with a bet.

I was researching LED grow lights for an article on another site. In order to justify the higher production costs of some of these units retailers bamboozle a poor girly with science, and I was forced to draw hard on old “A” Levels, Campo’s 2 years of college horticulture and a fast-track online learning curve in order to make sense of some of the claims made and translate them into hopefully understandable english.

(you can read a copy of the article here)

“You know” I said .. “I think we ought to try these”. We have heat issues where we live which pretty much rule out anything but outdoor grown weed for half the year. “Hmmm” was the reluctant reply. The issue being of course, not simply the higher initial cost, but proof of the efficacy of these lights to grow good bud. After all forum posts tend to be either by newbies – and who knows what problems they might bring to bear on any grow?, or by experienced growers – and who knows how much they’d have got if they’d stuck with good ol HPS?

The only way to find out if these LED grow lights actually perform like they claim was to pit one against an HPS system. Same plants, same environmentals, same grower. Reading around the forums, we decided to write to Fero-LED. They acknowledge what their lights are being used for and seemed interested in developing a good system. So we challenged them. “Fancy putting your money where your mouth is?” (or words to that effect). Surprisingly the reply was a typically Canadian “Awesome!” … and we were off, bets were on and we set out to answer the question:

Which is the best grow light for a closet grow?



Anyone who has looked into LED grow lights knows that for the small time personal grower, LEDs have all the advantages:

  • low energy useage that won’t impact noticeably on your electricity bill
  • long shelf life
  • small compact unit – simply plug and play
  • light and easy to adjust heights etc
  • quiet
  • no heat issues needing to be resolved with additional equipment. A small bathroom sized extractor fan necessary for airflow, not something that sounds like jet aircraft are taking off nearby.
Against this comes the price: you can pick up a decent 250 watt HPS for 150$ from amazon whereas the 360 4G Fero Apollo LED grow light  we were trialling is 550$. We all know the arguments about how a LED light will last a lot longer, whereas you will have to renew the bulbs in a HPS system at least every 18 months, and you’ll probably have to replace the ballast and even the reflector as well long before the LED fails. Add into that the extra cost of a bigger extractor, higher energy bills and so on and the price of the LED doesn’t look so bad.
BUT as Campo says, all the equations in the world don’t mean a damn if the things don’t work!
 Ok so here’s the set-up. Campo built 2 rooms, 45cm by 90cm within a larger grow space.  Both areas had fans for air movement, but a thermostatically controlled extractor operates within the room as a whole.
Because of concerns over growing new seedlings under 250 watt HID – and because we wanted to test out the new LED 357 light, all seedlings germinated and spent their first 2 weeks in soil in 10cm pots.

led vs hps comparison

At first signs of sexing they were transplanted into larger pots in a coco-perlite mix and moved into their respective grow rooms. All plants were labelled (tippexed) directly on the pot so there could be no chance of mistake.

Each area grew 3 female MI5 autoflowering plants, and 1 fertilised MI5 mother plant. By day 22 you could tell the difference in vegetative growth: nodes spaces were shorter under the LED, but given that these were always going to be fairly short autoflowering plants, we weren’t entirely convinced as to whether or not this would be a good thing.
 By day 39, things were settling into a good grow routine. We’d discovered some tips on LED growing and were putting them into practice. If any thing, we realised that the LED grow room was at a slight disadvantage to the HID one, simply because we were pitting years of experience with HPS against zero knowledge of growing with LEDs. However we reasoned this was fair enough, as this will be the same for any experienced indoor marijuana grower.
Things changed a bit by our next report. Unfortunately due to technical problems (I was the “dozy mare” who dropped the camera & broke it) there was a gap of 3 weeks between posts. During this time some major changes were implemented:
  1. The original Fero 357 (which only has a 120 watt draw) had been replaced by the new Fero4G 360 model (with a 256 watt draw). Plans had been to make the change earlier, so as to match like with like a bit more, but those nice men at customs had held up delivery.
  2. Plants were moving nicely into flowering stage, BUT we realised that there were within the group of 6 female plants 3 genotypes emerging. How much would these different genos impact on final result?
We decided to make a small change to the planting. On day 45 we removed the fertilised plants from each room – after all they couldn’t really add much information to the experiment, and added instead 2 Cream Caramel Autos just going into flower.

Read grow report (more bud pics!) for day 60 here

The 2 Cream Caramels were identical in form and size, and would we felt would help address the question:

Can LED grow lights make good bud?

Well, despite being pretty much the same as they started flowering properly, after 30 days under the different light systems, there was beginning to be a noticeable difference:












and no, I’m not going to tell you which is which. Be reassured that pots themselves were marked and never muddled up.

Read final grow report (day 66 here) 

Want to know the results of the LED / HID grow-down?

Well here’s a summary:



OK so the chart doesn’t scan in well (all the info is in the original posts anyway) .. so in case its too blurry to read, the final results are

LED – 193.2g

HID – 153.6g

which quite frankly is not what we were expecting at all.

When we went into this, I cannot emphasize enough that at best Campo thought the LEDs would produce comparable bud. Everything he had read on LEDs in articles, and as a super-mod, suggested that unless you were very experienced in their useage (and there are special techniques to growing with them) and combined them with all the gizmos (as most techno-LED growers seemed to) the results, certainly as regards flowering, weren’t all that.

But as day by day passed and I remembered why my moniker is “Weed Widow” as I lost my other half to the joys of the grow room, a few things soon became apparent:
  1. bud development under the LED was more “solid” to the touch than that under the little 250 watt HPS, where quite frankly it still felt loose and airy. The main cola buds on the HPS ended as smaller buds after drying: under the LED they remained as one big bud.
  2. light penetration was greater with the LED: I tried to take photos of this, but aesthetically they don’t work very well (I can post them if anyone wants me to!): the small buds at the bottom of the plants were actually forming into useable bud rather than just popcorn.
  3. there was, we felt, a noticeable difference after we swapped the 3G 357 for the new 4G 360 model.

We know there are some flaws in this trial. Here’s a few pointers we think ought to be made clear.

  • We don’t work for or have any professional relationship with FeroLED lights.  However, from our experience using their lights and our emails with the company, we would definitely recommend them to anyone considering buying a grow light system. The lights are solidly built, work well and the customer service is excellent.
  • As I said above, the aim of this particular test was to see whether or not LED lights really were worth considering for the small persy grower. Hence we pitched a small LED against a 250 watt HPS over just 4 plants.  YES, there is the possibility that the trial would give different results if we put say a 600 against the 4G 900 (with a 645 watt draw).
  • Genotype variance amoungst the MI5 seedlings was a disappointing factor that we hadn’t allowed enough for. Who can really say how much influence the 3 distinct types had upon the final result? Having said that one would expect the larger plants under the HPS (in one case twice the size) to produce much more bud than those  under the LED.
  • YES, some plants took longer to mature than others. The Cream Caramel under the LED, 1 of the LED MI5s and 1 of the HPS MI5s finished 9 days after the others. I don’t actually see that as much of a problem. Plants are ready when they are ready, not in accordance with a seed packet. And given that the LED Cream Caramel gave 66g dried weight against 36g for the same sized plant under the HPS, I think those extra 9 days were worth waiting for. Anyone who would do otherwise is quite frankly a fool in my book.
  • Re the comment that LED-grown weed tastes different. Campo has been toking daily (give or take the odd day) for only 19 years so cannot claim to be an expert. “I can’t taste any difference” he says, “I have a joint and I get well stoned. I’m happy.” So we gave some to friends as testers, they couldn’t tell either. The only relevant comment was that one person felt his 4g bag was smaller than his mate’s. They’d both been weighed the same, one just looked less (denser heavier bud). He had the LED.
  • whilst this was not a truly scientific grow it did aim to replicate fairly the growing conditions your average Joe Toker uses for a small personal grow. There were no high-tech extras. A diary was kept recording Campo’s observations throughout.
  • Grams/watt doesnt work out super brilliant for either grow, and Campo was very concerned about this throughout. The problem was not enough plants for each grow space – there were quite a few gaps. This is a problem with growing autos in pots, you just don’t get that sea of green effect.
Obviously this trial does leave some options yet to be defined. So I guess we’ll just have to force ourselves to do another grow-down. I think Campo was a bit hesistant before to committing a large part of his grow space and nearly 3 months of his time if the LEDs weren’t going to work well. Next up is the 600 watt HPS versus the 900 4G. We’ll use clones instead of seed grown plants to remove the genotype variables (we have some Amnesia mums coming along now). We’ll also use NFT and be able to measure nutrient uptake more accurately.
In the meantime, I guess I’ve won a bet (and that’s a fiver you owe me Campo) … and to anyone who says that LEDs can’t grow? Put it in your pipe and smoke it :)


Many thanks to Brent @ FeroLed for letting us test his stuff, and to Cannabis Seeds  for their best value around seeds. If anyone else believes in their product enough to get it tested honestly and openly, please contact us! (Household cleaning sales people need not apply) 

8 thoughts on “Drumroll please .. the Fero LED vs HPS 2012 grow-down is over ..

  1. matthew says:

    have some questions for…brent of fero told me to talk to you…

    i am in europe too, i think an hour ahead of you…

    can we talk ok skype? angus.macguyver is my id

    thanks :)

  2. Mike says:

    Hey dude,

    Glad to see someone else is using LEDs! Cheers mate. I have been using them for over a year now, very happy with the results.

    I use Super Grow LEDs, but am open to try other companies as well. Do you notice that the quality of LEDs is better than HPS? Is that the same for you?

    Visit supergrowled.com when you get a chance and take a look, I’m looking at the lights you used now. Good luck with future grows, take care

  3. Weed Widow says:

    yeh personally I reckon LED grow lights are great .. I’m a little sceptical though about companies like supergrowled.com which reckon that a 92 watt led will equal a 400 watt HID. I think the LEDs are about 25-40% more efficient .. but then you get added bonuses like longetivity, reduced additional costs with extractor size etc. Once you look into the site though maybe they are talking about the equivelant for growing plants slightly less photophilous than weed though .. But I will have a better look around their site. Thanks for the comment :)

  4. sophiaperry says:

    I have heard a lot about the LED grow lights but still I am aware of the fact that its not enough ever when it comes of the knowledge. I think people should use the LED for the better results. This will surely result into the beneficial yet productive aspects.

    • weed widow says:

      I think that depends a bit on where in the globe you live – I think they’re pretty common in the US and many medical grow setups there now use them just because running costs are lower, they don’t have to worry about expensive equipment being confiscated and quite simply LEDs make growing easier. Does it make for better weed? Well its certainly tighter and more dense – which appeals to me ..

  5. James says:


    Does anybody know if they could answer this for me please? I have an aquarium LED, an AI vega, which is usually used to grow full reef coral aquariums. Here is the spec of the unit. I am new to growing and I am curious as there is little information out on the forums or internet whether this would be substantial enough to be able to grow. I would appreciate any help thank you.
    The Unit will cover a 24×24″ area
    LED unit is 95w
    LED’s in unit:
    (4) Cree XM-L Cool White
    (8) Cree XP-E Royal Blue
    (4) Cree XP-E Blue
    (4) OSRAM OSLON Deep Blue

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