Is it finally time for LEDS?: Cree XP-G

[calvin_orchidL]

"Oh no..groan, not another LED light thread?"

There's been so much back and forth on this topic, and the plant growing world is riddled with badly run experiments, hype, and tons of 'theoretical' information based upon PAR, wavelengths, lumens etc...One problem is that people have been choosing sides and advocating opinions that aren't grounded in true or reproducible results, and then other people take these statements for truth and this is how ungrounded ideas are propagated.

I'm hoping that I can share this info with the orchid growing community, so you won't feel the need to go sifting through pot growing forums or buying cheap crappy LEDs from China on E-bay to experiment with. This is the story pure and simple; I'm not advocating for their use, nor am I able to prove that they work (yet) as I have only been running mine for a month.

I first started becoming interested in LEDs due to their low energy consumption and low heat output. Growing intermediate in a tank under T5s was getting too warm for me, so I needed solutions. I started my research like many of you on plant growing forums, and very quickly got lost in the huge mess. I turned to the reefkeepers. The reefkeepers have been dabbling in LEDs longer than us, and more seriously as well...furthermore, they are not contaminated by the commercial influence of a cash crop named MaryJ. Although most info I found revolved around coral growth, I found this blog which inspired me to try my own LED setups:

Ken's Aquariums & Pond

Ken caught my attention when he posted photos of his planted tank (aquatic plants) showing growth after 6 months under LEDs. His website has details on how he did his DIY setup.

What tipped me over the fence was when a grower on another forum demonstrated photos of his tank that utilized the same Cree XP-G LEDs. He has now posted photos of his tank 11 months later, and the plants are growing and blooming. (PM me for the link if interested, since I don't know the policy on posting links to other forums here.)

Here is a photo of my setup. I have 12 Cree XP-G LEDs running at 1000mAmps (can be driven to 1500mamps). There is a ratio of 1:1 neutral whites to warm whites. I mounted them on a heat sink, soldered them together, and then soldered them to the driver. The light measured 6" under the lights are over 5000 foot candles.





Costs:
LEDS - 5-6 dollars each (total around 60 bucks)
Heatsink - Predrilled and pre-tapped: 20-40 bucks (can get it cheaper if you don't get it pre-drilled/pre-tapped)
Soldering - 20
I also had a friend build a light hood for me - basically a piece of plywood primed and sealed, with a hole cut in it to accomodate the LEDs.

My impressions so far:
1. I grow intermediate to low light plants, so this works for me. A setup of two of these arrays is replacing a 6 T8 tube setup (72 watts vs 240 watts) and I am much getting higher light than before. Cost for both setups is around $250. Cost for the T8s (fixtures + bulbs) was around $80.

2. The DIY aspect was daunting at first (I am not an electrician nor a DIY type) but in retrospect it was quite straight forward. It would have been easier if more aid was available online, but unfortunately this was not as abundant as I expected. Nonetheless, there are now plug and play kits available which have absolutely everything you need, no soldering needed (except to connect the driver). I tried one out and they are a beauty to work with.

3. The light spread is quite narrow, leading to a focused area of intense illumination, which drops rapidly as you move away from directly under the lights. I plan to mitigate this in future setups by moving the lights higher from the plants, and geting a larger heat sink which allows the individual LEDs to be separated from each other further.

4. The temperature difference is VERY noticeable. Even with T8s, I had some heating up of the tanks, which was undesirable in the winter, and quite bad in the summer. With my T5s, this was downright horrible. The temperature in the tanks are now complete ambient.

5. Plant growth has not stopped this last month. In fact, roots are growing better, and I am getting some spikes. This could either be due to a) the drop in temperature, which suits these plants better, b) an increase in light levels from the LEDs, c) increased humidity due to the new hood which seals moisture in better than my old one, d) seasonal change, or e) some unknown variable that I haven't thought of yet.





Anyway, hope that was helpful. Again, it has only been a month. But I will update and answer any questions to the best of my knowledge. Hopefully this can become a resource for anyone interested in trying these lights out, and also dispel/validate some of the theories associated with LEDs and orchid growing. PM me if you're interested in finding out where these supplies can be found.

[Wjs2nd]

Very cool. I currently have a blue/red setup (I bought). I can not wait to see have everything does the next few months. I am able to bloom vandas und my current setup.

[LinhT]

Calvin, are you still running this setup? Are things still growing well?

Also, what is the wattage of each light? I read over your post twice but did not find the wattage. I've poor reading comprehension so my apologies if I missed it...

[skanderson]

his leds are 3 watt cree xpg. he said he is running them at 1000 milliamps. alot of people in the reef community run them at 700 milliwatts to extend their lifespan. the higher the amperage they are run at the harder it is to keep them cool and high temps lessen the lifespan of leds. if you are thinking of doing a similar build now the most efficient leds you can get are cree xlms. they are slightly more efficient but can be run at up to 3 amps each. they are also 3 watt emitters. you end up with more money per emitter but fewer emitters to get the same par.

[calvin_orchidL]

Tracy - things are still growing well! I have 2 more setups coming along with some modifications, including spreading the units apart on two heat sinks to distribute the relatively narrow light range of the LEDs

Skanderson is correct...I believe they can be run up to 1.5amps but I don't remember. Thanks for bringing those XM-Ls up - I wasn't aware!

[LinhT]

Ok, thanks Calvin and skanderson. I was trying to figure out if it's better for me to set up something like this or to just get another Kessil H150 32W.

Technology changes so quickly even in the world of orchids. Just 4 yrs ago, we were all about the T5 tubes.

[greenpassion]

I have to jump in here. I bought 6 LED bulbs from Orchid Web around 10mths ago, and they are around 2 1/2 to 3ft from my orchids, which are placed in a 1/4" thick glass sheet 4ft. long x 15"wide. I have a heat mat that fits that exact size on the glass, and a mirror again that size on that. My orchids are in S/H, and there is a small fan keeping the air moving. When I first joined this board, I had gotten info that the plants wouldn't do well unless I had the red and blue (disco !!) lights over them. I found it hard to believe that a company that specifies in orchid culture would sell bulbs that would not do the trick. My experience has been that these natural light and warm white LED's are just fine. I use 4 bulbs that are 7w, 38 degree cri of 80 , and 2 chip tec bulbs on the ends of the track. Go to that site and check out these bulbs. My set up is way way simpler than some I've read about here, and I have 4 different kinds of orchids all doing wonderfully. I hope I am not in trouble for mentioning where I got the bulbs...