By gisette
LED Experiments
Submitted on Sun, 2010/01/24 - 6:46pm
Last updated on Wed, 2010/04/21 - 10:36pm
Posted in
Doing some systematic testing of my new 16W triband LED bulbs. I've seen a lot of claims about LED grow lights on the web, and little evidence of those claims.
The key claim I'm interested in, is that because LED growlights focus on the red and blue wavelengths used most in photosynthesis, in practice LED growlights can use less electric power for the same growth. And added bonus is that they're less bright / obnoxious to the human eye, because the human eye sees green best. IMO, this bonus is pretty much lost, as lurid magenta light is at least as obnoxious. 
I was deeply relieved that the "3rd generation" triband LEDs (with full-spectrum white LEDs added to red and blue) proved to be much better looking. If still pretty weird.
See Triband LED grow lights for initial pictures of the lights.
But it remains to be seen whether they yield superior growth to equivalent-wattage fluorescents.
Update 4-21-2010: These LED's provided vastly inferior growth to equivalent-wattage fluorescents. They were so bad, that I wouldn't use them even as auxiliary lighting, because they made tomatoes grow spindly even though they were added to sufficient fluorescent light.
But - HTGSupply is a wonderful company to do business with.
Thu, 2010/02/18 - 3:36pm
#2
Agreed, this video sells the product well. They also seem to know what they are talking about in their answers to various comments, in particular the PAR vs lumens which always comes up in forums arguing about their worth. You invariably get some mis-informed person who tries to compare his lumen output against the LED...
When I did my cuke, I said at the time that the plant looked more 'lush', I want my lettuce out of the raft now and get onto another cuke in aero!
Interesting with the light height though, I was under the impression that the UFO height was 10 to 15 inches above the plant. When I had mine close to my cuke it burnt it?
What I also read was that a particular height allowed the different LED's to mix properly before falling onto the plant, how true this is I don't know.
Thu, 2010/02/18 - 4:34pm
#3
Well, your lettuce will be done soon. 
Interesting re the cuke getting burnt too close to the light. Cuke leaves are more tender than tomato leaves, though. My weak LED spotlights aren't burning anything - and my tomato leaves are pushing right against them now. But the idea that some distance allows for a more balanced diet makes sense - each chloroplast would want a nice mix of light. But there's that intensity falls off with distance thing, too... Hard to trade off.
Hm. Now I'm thinking I should raise my tomato LED spots again. 
Despite the fact the tomato's been stretching...
Sat, 2010/03/27 - 2:23pm
#4
Something of interest gisette, there's a lighting grow test over at GardenWeb - he's pitting HID vs CFL vs LED against each other.
I'm still awaiting the return of my LED UFO which is annoying, I want to get on and try a cuke in my aero/hydro unit...
Sat, 2010/03/27 - 5:19pm
#5
Thanks for the link, Peat. Interesting, though I wished he'd compared like-wattage bulbs. Like, I believe he'd have gotten the same CFL-is-growing-better from a 14W CFL vs 14W LED. How a 125W CFL compares with a 14W LED should be a no-brainer. Though those plants appear to have been poisoned somehow. (Too much light?)
Sat, 2010/03/27 - 5:35pm
#6
Granted, it's a shame it's not equal. But, the CFL has got better results than the 400 watt HPS and the 125 watt LED looks rather poor, not what I wanted to see because the LED was going to be my future replacement light!
Sun, 2010/03/28 - 6:47am
#7
I hate to put a damper on things, but my neighbour bought an LED UFO - circa 225 LEDs for £120 all-in - and has now ditched it permanently.
He tried several grows with different veggies and flowers and had to abandon all those that seemed to reach above a certain height. It would appear that while the LEDs are undoubtedly within the favoured wavelengths for plant matter, it does not have the penetrating power to reach down the whole of the plant to sustain it properly. That is why, we think, it worked only for small plants. Perhaps if there were to be a 100cm high board of LEDs that was placed up against a plant then taller plants might survive. However, at current prices it is certain our wallets wouldn't survive quite so well!
It's an interesting development and one I will be watching. It has always been known that "early adopters" of cutting-edge technology will always pay the price for that privilege. I shall, however, be happy to be a 3rd generation adopter and let others before me feel the ravages of product development. It's going to be HIDs for me for the next 5 years at least. However, did you know there is also another bulb that is poised to make HIDs look like a tea-candle? It is a plasma bulb by Philips (of course); it uses more or less the same leccy but the lumens are nearly double. However, this bulb presently retails at around £1000 all-in.
Sun, 2010/03/28 - 9:26am
#8
I completely agree with you on the point that LED's cannot, yet, compete with the HID's, but they do work - albeit, not for your tall tomato type grows perhaps where the issue of the light falling off hinders them.
There are a number of links on the net where a number of users have grown a variety of plants successfully, good reading here and here. I considered the subject very carefully before I bought my 90 watt UFO, if the thing had not gone wrong on me then I was hoping to show it's potential off here - I was a previous HID user before I moved house, I just don't have the space at the moment to get back to this way of growing, that's why I'm currently limited to CFL and now LED, once I get mine repaired then I'll get onto a proper grow and see how it gets on.
Interesting about the Philip's bulb, I wonder how long before this gets into a reasonable price bracket.
Sun, 2010/03/28 - 11:46am
#9
Curious, that. Your LED unit needs repairing? I thought the idea of LEDs were their higher reliability? May I enquire; what went wrong?
The cost of the Plasma bulb will come down proportionally to the Sales against Research & Development costs and competitor activity, especially when the opposition reverse-engineers the Plasma and creates a clone that just bypasses the patents. For the likes of me, that's not any time soon! I love your posts, Peat, I hope they keep comin'.
Sun, 2010/03/28 - 11:52am
#10
I'm specifically trying to find growing lights for use in living spaces, and CFL seems to be the way to go. Rather than going for one ultra-bright light that reaches down, I'm using multiple lights.
So far so good on the low-wattage CFLs with tomatoes and peppers and brassicas. But I've ditched all the low-wattage LED spotlights - they didn't appear to be good for much of anything.
Sun, 2010/03/28 - 1:30pm
#11
The light packed in when I was doing my lettuce raft grow, you can see my frustration at the time. Most of the LED's stopped illuminating, now, the LED's are probably very reliable - it's the circuitry that goes with it that has probably let me down, perhaps this was poor quality?
My 125 watt CFL has done me fine so far, although I would love to get a decent HID. I could not vent the heat enough to live with it in my grow room unfortunately - things would be far too hot for the cooler crops.
Sun, 2010/03/28 - 2:38pm
#12
I have used LEDs since the early-1980s, but not for horticulture but electronics. LEDs are solid-state and are therefore inherently reliable. The only other component you need apart from power is/are resistor(s), which limits the power to the LEDs so that the equipment runs at its most efficient. I have many projects from the 80s in which LEDs are still working today, they are that reliable.
However, during the last 12-18 months there has been many reports of sub-standard LED/electronics originating from Asia - esp. in cannabis-growing arenas as complaints from them are not likely. I would politely suggest that either the components are poor, resistor(s) have burnt out (likely) or the power supply wasn't up to the job. In most cases, replacing the resistors for a higher wattage and same ohms-value and a bit of soldering will regain full working order of your LED UFO. Your repair should cost pennies, literally (exc. labour).
You may wish to re-think your HID options; copper-coil ballasts are cheap and you can place your ballast on a chunk of metal to act as a heatsink as well as locating your HID outside your grow area. The lamp-heat can be easily dispersed with a fan. HID options at 200-1000watts means that most grow applications will benefit from the superior bucks/lumens output that HIDs offer. Certainly I can buy a HID ballast and bulb for less than a LED UFO.
I feel for you; I'm gutted for you that your UFO should fail and your investment is spoiled. I wish you a speedy return to full growing-power.
Sun, 2010/03/28 - 4:31pm
#13
The grow room is an old airing cupboard, I have a ventilation fan sucking air out but the air coming in is a room temperature. This is warm so the grow room will never get below this temperature, I need to vent in cold air to get my temperature drop - herein lies the problem... I can vent out as much as I like but it won't help in the end, so you see the issue I have with heat.
I would not buy a copper coil ballast though, I used to have an electronic one which ran much cooler than the older versions, plus, they are much better for electricity consumption and HID lifespan.
The LED I bought was, supposedly, from a UK supplier who touted it's quality; I purposely stayed well clear of the cheap China imports as I wanted quality over price. I can only take the company on face value, I hope that what I have been supplied is not something inferior... They back it up with a 2 year warranty so that's something, it's still under warranty so there are no problems with it's pending return.
My background is electronics, if the LED was outside the warranty period I would be straight in there with the old multimeter, I longed to pull mine apart but that would void my warranty - maybe one day. 
Thank you for your help, I value your opinion and discussion, it's good to talk with someone with kindred knowledge.
Wed, 2010/04/21 - 10:42pm
#14
I'm delighted to report that HTGSupply - the company I bought my LED spotlights from - agreed to refund my money, even these months later, due to just how badly these LEDs performed. They were sold as growlights, more energy-efficient than CFLs. They failed to be growlights.
HTGSupply no longer sells this product.
But when my first spotlight broke, they replaced it, including shipping, at no charge. And now they're willing to refund me for the other spots, too. (Those I'm returning to them - the broken one, he said not to bother.) I should have asked long ago.
Bad product. But a very good company.
Thu, 2010/04/22 - 9:41am
#15
It looks as though I have a bad product and a bad company...
They are going to send another UFO, but when is another matter, when never seems to come and it's up to me to chase all the time.
There is no way I'd buy from them again, if anyone wants an LED then stay away from EasyGrowLED as the lights are actually China imports which they have said in correspondence, I fear the new one will demise prematurely as well...
Thu, 2010/04/22 - 1:45pm
#16
I'm gutted for you, Peat, I really am 
Be a 6th generation adopter like me, let others find out the hard way,
and then when/if it works let them refine the product/s and reduce the price -
then buy it!
I hope you get a satisfactory outcome (ie your cash back)
Thu, 2010/04/22 - 1:51pm
#17
Definitely, Kevin - I'm not trying this technology again for 5 years.
Though - they already have LED panels they call 6th generation. 
I also read somewhere the other day that the LEDs are really bad for your eyes. I can believe it.
Sat, 2010/04/24 - 3:45am
#18
There should be no problem with getting my money back, I paid by credit card so can do a charge back against them, or, take the whole useless company through the small claims court...
Sat, 2010/04/24 - 12:03pm
#19
Well, do it as quick as you can - their website is down and so might the company be and into administration.
Call your Credit Card company without delay, really.
Tue, 2010/05/25 - 1:29pm
#20
Good news with this at last, I have had a full refund from the company - only took them since 11 March to get this sorted though!
I've now found another supplier (CTLEDlight) which looks much more professional, they are using a better light spectrum and you can specify what you want, I do still want to pursue the LED route and get a decent grow out of them... stubborn gardener 
Tue, 2010/05/25 - 3:09pm
#21
Curious to see how it goes for you, Peat! Congrats on finally getting your money back from the last place.
Tue, 2010/05/25 - 4:55pm
#22
Thanks, it did test my patience.
I'm still reading all I can on the LED front, it seems a 60° angle is much preferred over the 120° one I originally had. With this company I can specify the beam width and also select the better 660nm spectrum, which seems to be one of the better reds out there.
There's a company called Hydro Grow LED over your side of the pond, I've seen many posts and plenty of positive results with their brand of lights, they are using peaks at 440nm, 470nm, 640nm, 660nm which have worked very well. The closer I can get to these the better it will be for me, the other light didn't hit these peaks properly; perhaps that was why it performed poorly as far as I was concerned?
Anyhow, this will be a future purchase once I've moved...
Peat - Ooh, a good LED test video on YouTube.
Yes, these people are trying to sell 90W UFO LED growlights. But - they do a very good job in that video, showing side by side controlled test conditions, growing early girl tomatoes, several varieties of 90W LED rigs vs. HPS, and grow to tomato harvest.
They mentioned that they tried lower wattage lights, with too little success to bother with.
But I was heartened to hear that the LED tomato plants grew a deeper green, as mine is. (My CFL tomato looks lush and sturdy - except that it's yellow with purple undersides of leaves...)