I and others here have spent so much time trying to get new growers to not waste their money on LEDs, I thought it would be best to have a topic on why they are not any good for growing cannabis. Bottom line is that they are not intense enough and cost too much.
I'm not going to bother with mentioning all of the unfinished LED grows diaries here, or the dismal results gotten by folks brave enough to finish a LED grow diary (oops I just did). However I do invite knowledgeable growers with experience to share their views and for the scientific and technical minded out there to share their disciplined knowledge in refuting the claims made by LED sales people and manufacturers.
What I want to do is share some information I have recently gotten ahold of. I was recently at a buildings trade show and picked up some trade show magazines on architectural LED lighting. What I found, despite the obvious hype you would expect, (trade shows are, after all, just portable/temporary shopping malls specific to that trade, with a few classes and speeches thrown in) is some very interesting and real world tests and analysis.
The magazines I'll be taking quotes from are LEDs Magazine June, 2011 and BeLight volume 7, 2011.
Here we go.
LEDs Magazine:
The first article to catch my eye was one titled, Field trials of LED outdoor lighting demonstrate benefits to potential adopters. The article was written by Philip Jessup, Director of International Lighting for The Climate Group. An orginization looking at technology to help us reduce emissions world wide. A nice sounding name, but basically a front for a group of businesses trying to muscle in by using climate change as a motivator. IMO.
Anyway. These folks conducted astudy of several cities (NY, London, etc) who are trialing LED units for street lights and other municipal areas (garages, tunnels). New York cities DOT (department of transportation) has liked the results so far and are buying more units.
Quote
...that among the nine LED products tested, several have exhibited excellent performance over the past year, matching or approaching the illuminence of the baseline while delivering significant energy savings, very good lumen maintenance and negliagable color (CCT) degradation.
Emphasis mine.
The key note here I want to underline is that this study only lasted a year. This theme will come up again.
In Canada they did a study using LEDs and T5s (fluro). Apparently the LEDs couldn't do it on their own.
The study was for about 2.5 years this time. In this study, they found that the publics perception and acceptance of the lighting to be very good. Residents thought they were brighter than the HPS fixtures that had been there despite a designed reduction in illuminance by about 20-30%.
The article concludes by saying that public perception of LED luminares was good and was a driving factor in acceptance by politicians. However cost still remained a significant hurdle.
Another article is by Maury Wright, the senior technical editor of LEDs Magazine. This is about the city of Raleigh in North Carolina (USA) which is one of th efirst cities to adopt LED lighting for street lights, through a partnership with Cree. The first part involved 188W HPS fixtures with 144, 70 watt LED fixtures (note they don't mention how many HPS fixtures had been replaced). This project has been documented for over 4 years now. The fixtures were on a dedicated circuit so cost savings could be well documented. In energy and maintenace, the fixtures have saved the city over $13,000 per year. Note they don't say hw much the fixtures have cost or what percentage of the savings was due to energy savings.
Here folks thought the fixtures were brighter (and safer) as well even though the fixtures cast 11% less lumens. So again, less light is being achieved with LED fixtures. Also noted was how LED fixtures survived a tornado and vandalism. It was also noted how LED technology has advanced since these Raleigh projects ahve started and with the new technologies, they can use less LED lamps to achieve the same effect.
BeLight magazine:
A quote from Alan Kuan (TTiC Lighting vice president);
Quote
The critical technology for downstream product is heat dissipation for electronic component.
So much for heatless lighting. Every major LED lighting device seen in these magazines has massive heat sinks.
Currently the best offer from Cree on LED lighting is a family of fixtures designed to replace linear fluro fixtures. The CR series is dsigned to have comparable output of T8s (remember the quotes from the other magazine about apparent brightness) and offer a payback of inside of one year compare to the same fixtures. The heatsinks on these things are big. Apparently aquarium enthusiasts think these are barly sufficient for aquariums, and certainly not good enough for coral growth. Despite my looking all over the web, I couldn't find a price for these units, but a lot of columns stating how wonderful they are. :g:
Another interesting element were the articles claiming that LED testing and manufacturing needed vast improvements.
So this mag did not have as much for me to play with. It was far more techincal and sales oriented thean the other and really, just a big glossy ad for LEDs.
So what am I getting at here? Several points. Real world testing of LED lighting is still in it's infancy. LED lighting is almost as good as fluorescent lighting in terms of brightness and usability. And these are for the very best, high end (read very expensive) units now available.
Some folks like to say things like NASA uses LEDs, they've advanced so far, etc. Well, the reasons why people use LEDs (like NASA or cities) is not to grow cannabis with.
There are other reasons for them that make LEDs compelling. But even that is still mitigated by the cost. And there are reasons to believe that LEDs are reaching a technological dead end with how bright they can be. Unless of course some very innovative technologies are developed. Which won't be cheap.
At this stage it is my opinion that LED grow lights are crap. They cost too much money and do not do the job. It's possible they may someday be useful for growing cannabis, but they are not miracle lighting units and will generate heat and use just as much electricity as an HID I predict. And those units will not come soon.
Save your money, ignore the hype and buy what has been proven to grow incredible cannabis. There are no short cuts.
I know, I've tried.
