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LED plant lights?

would it be possible to use high power LED (light emitting diodes) as a plant lights? The kind i am reffering to are the ones commonly used for DIY reef aquarium lighting. they are sold from www.reefledlights.com. would they be to bright and burn the plants? Also, what colors would be the best to try? any ideas????http://terraforums.com/forums/images/smilies/dunno.gif

---------- Post added at 06:31 PM ---------- Previous post was at 06:29 PM ----------

and why is there a random iternet adress next to the confused smiley i posted?
 
nope. inappropriate wavelengths apparently... i've entertained the thought as well.

the LEDs that are actually used for horticulture are quite expensive as well...
 
I've seen LED's sold and used specifically for plants, so I don't think I agree with the innapropriate wavelength idea (sorry). Most plants use approximately the same wavelengths. The main problem with them is that they are pricey, as Amphirion stated. Also, I don't know how high the light output is. You would definately save on electricity costs though.
 
I think amph meant that those specifically marketed for reefs probably are going to be the incorrect wavelengths.

I'm not sure what the exact savings would be in terms of energy but in terms of up front cost it seems that fluorescents (specifically T5s if you can remove heat) are the cheapest route for high light output.

I know that in the planted aquarium community the general feeling is that LEDs are not quite there yet, and I feel the same way in regards to CP growing too.

Just my opinion though...and to be quite honest I would love to see someone take a stab at the commercially available LEDs and CPs and see what happens. If anyone wants to volunteer (or has tried already) that would be great! ;)
 
would it be possible to use high power LED (light emitting diodes) as a plant lights?

Yes.

would they be to bright and burn the plants?

It's just a matter of wattage and lighting distance, same as with fluorescent and other lamps.

Also, what colors would be the best to try?

LED light color "white" or "cool white" is OK for growing plants.

When doing DIY projects with power LEDs, please be aware that the LEDs should always be powered with constant current drivers and that they need proper cooling from the first second of usage, or you can burn out your valuable LEDs in less than or just a few seconds.
 
I've been toying with the idea of LEDs as well... But yes, the ones sold for reef tanks are totally the wrong spectrum. Even a reef tank "white" is typically no lower then 8000k, usually 10,000k, mixed with blue bulbs.

I really like PAR38 bulbs, as you can screw them into a normal light socket and they are BRIGHT. Like a floodlamp. You'd prolly want to look for 6500k at least, or if you wanted to vary your light, mix it with a 3000k bulb.

http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=16DNB9WEHT9KA8Y8SYBR
 
I've been toying with the idea of LEDs as well... But yes, the ones sold for reef tanks are totally the wrong spectrum. Even a reef tank "white" is typically no lower then 8000k, usually 10,000k, mixed with blue bulbs.

That's too much blue. I would not mix blue and white LEDs, as "white" LEDs already give a lot of blue light themselves, especially "cool-white" LEDs. Too much blue prevents the plants from length growth. Especially with Nepenthes you can see the inter-node distance between the leaves shrink very much when lighting with cool-white LEDs, they grow much more compact and stay smaller with the same number of leaves developing.

It's possible to use "cool-white" for plant growing, or a mix of "cool-white" and "warm-white" LEDs (but warm-white LEDs give you less lumen per watt, so they are less efficient).

I really like PAR38 bulbs, as you can screw them into a normal light socket and they are BRIGHT. Like a floodlamp. You'd prolly want to look for 6500k at least, or if you wanted to vary your light, mix it with a 3000k bulb.

For my small LED lighting constructions I mostly use affordable Cree XR-E LEDs, pre-mounted on hex-star plates in a "cool-white" color selection. I think this is a selection of 6.750K...7350K.

I just glue the hex-star LED on a bigger aluminium plate for cooling and they are ready for cabling (soldering iron needed). Needs only about 10 mm (0.4") headroom for the lighting, so you can install such lights in very small growing cases (you can place the constant current driver somewhere else).

You could even install a LED lighting in one of the famous "Lowes Death Cubes" and keep a single carnivorous plant in the darkest bookshelf within the house.

You see the Dionaea used as my avatar picture?
This one is only lighted by 1 Watt LED power (Cree XR-E, cool-white, @350mA, 14 hour lighting period by timer switch) in a plastic cube.

LED lighting is a very good solution for very small setups.
But LED lighting becomes very expensive for bigger installations, so for bigger installations fluorescent lamps plus effective reflectors are the better solution.

This plant is another one grown under LED lighting (photo taken under natural light):
Drosera_schizandra_shade.jpg


And this one is grown under LED, too (even the photo was taken under LED lighting):
D_spatulata_Tamlin.jpg
 
  • #10
jesse: hmm... a not-so-deadly deathcube... i think i might want to try that. i was thinking about lighting a small terrarium or grow rack anyways, so i might want to try LEDs out. i have a soldering iron and am pretty good with it, so hooking up the LEDs wouldnt be a problem. now i would only need a driver, a heatsink, and of course, the LEDs themselves.

---------- Post added at 08:20 PM ---------- Previous post was at 08:14 PM ----------

i just remembered, i have an old cpu heatsink in the basement, but unless i want to use it for the "lifecube" thing, i would need a metal plate of some sort, and attatch the heatsink to middle on the back.
BTW those dews and the flytrap look great. i especialy like that notched sundew (it is Drosera schizandra, right?)

---------- Post added at 08:26 PM ---------- Previous post was at 08:20 PM ----------

i actually have a reef tank (40 g), so i might also want to use LEDs there

Or rather my brother has a reef tank, but i find it sooo awesome, i wish it was mine, and he might want to use my idea to use LEDs :jester:
 
  • #11
How do you think something like this would work, for a closed box?

http://www.cheapvegetablegardener.com/2009/01/cheap-led-light-and-grow-box.html

Yes, that works OK for a few thousand operating hours,
- if you use white and super-bright LEDs
- if you place enough LEDs per area

I'd say for light hungry species (Dionaea, Sarracenia seedlings) you will need around 3 low-power (operated @20 mA) LEDs per square inch, so for a 8" by 12" box = 96 square inch you'd need 3*96 = 288 LEDs.

For less light demanding plants like D. capensis, D. schizandra, U. sandersonii maybe a little bit less LEDs. Such low-power LEDs have only very little lighting power per LED, so you need many of them.

About the "closed box": Before putting plants into the box, I'd check the temperature in the box after the LEDs are operating a few hours. Perhaps you will have to place one or two holes of a proper diameters in the lid or the sidewalls to provide some ventilation/cooling.

Unfortunately such cheap noname LEDs in chains of light from China have no big lifetime. They become darker after only a few thousand hours of operating time, or they become totally defective and stay dark. And if single LEDs in the light chain becomes defective, the light of the whole chain can be affected, like no light at all after only one defective LED. Or all LEDs glow much darker after only one LED in the chain has become a darker glowing. Or (as happened when I tested low-power LEDs): Most of the LEDs become much darker, only very few stay super-bright as they were initially.

After one year of usage for plant lighting (that's about 5000 operating hours), my low-power LED installation was pure crap, no lighting power any more. My estimate is that more than 75% of the initial light/lumens have been lost within 5000 operating hours. So I cannot recommend low-power LEDs for plant lighting or you must replace them relative often.

It's not worth to use low-power LEDs in high quantities, I think.

On the other side: Quality high-power LEDs made by a brandname manufacturer are much better. Such high-power LEDs have a higher electrical efficiency, which means they make more light/lumen from the same electrical energy. And they last much longer without losing so much of their initial lighting power. Also you need much less of them and the headroom in the growing chamber needs only 0.4" of installation headroom. So for small lighting setups, they are nearly perfect.

---------- Post added at 12:10 PM ---------- Previous post was at 10:54 AM ----------

jesse: hmm... a not-so-deadly deathcube... i think i might want to try that.

I'd give it a try if you want to do a LED plant lighting experiment.

i have a soldering iron and am pretty good with it, so hooking up the LEDs wouldnt be a problem. now i would only need a driver, a heatsink, and of course, the LEDs themselves.

And some thermal 2-component glue to fix the LEDs on the heatsink.

i just remembered, i have an old cpu heatsink in the basement, but unless i want to use it for the "lifecube" thing, i would need a metal plate of some sort, and attatch the heatsink to middle on the back.

Here is what I use:

Heatsink: I don't use fancy heatsinks, just simple flat aluminium plates, cut to size as needed. I glue the LEDs with its hex-star on the aluminium plate, ready for soldering the cables. I calculate with roughly 5 square inches of aluminium plate per 1 watt of LED lighting as a heatsink. The plate then gets hand-warm when the LEDs are in operation. The aluminium plate can be fixed to the lid of the box or mini-terrarium with glue or some screws. Or even with double-sided adhesive tape if the lid is flat as the plate.

LEDs: Always buy pre-mounted LEDs on small "hex-star" plates, do not purchase pure "emitters" only! Also buy quality brands with a high lighting efficiency. For my LED lighting experiments I'm using mostly these "CREE XR-E cool-white" type LEDs, directly imported from HongKong:
http://www.dealextreme.com/p/cree-xr-e-q2-emitter-with-star-2395
I don't know the customs regulations in your country, but here in Germany I can import things of around 30 USD worth per purchase without paying additional customs or sales taxes, so these are the cheapest way for me to purchase good LEDs at a reasonable price. When ordering 3+ and clicking the "bulkrate" option at Dealextreme, they will send the LEDs by registered mail. Time of delivery to Germany is around four weeks in average.

Thermal glue: Don't purchase the "grease like" thing, you need a 2-component glue instead. Until now I mostly used a relatively expensive "2-component thermal glue", but as I power my LEDs mostly with 350 mA only (that's much less than the maximum rating for Cree XR-E) I will use another cheap all-purpuse 2-component glue in future.

Soldering: LEDs are diods, so you must observe + and -, don't mix it up.

Driver: Always use "constant current drivers" and no fixed voltage adapters with LEDs. The constant current drivers at Dealextreme are cheap, but pure crap. Buy the LEDs there if you have no other cheap source, but don't buy constant current drivers at them. Here I use some very nice insulated drivers that I can directly connect to EU 230 volt mains power that need no extra casing or extra AC/DC adapter. If you need a driver recommendation, please name me one or two web addresses of Internet shops with LED equipment and I can lookup what is suitable. Unfortunately I cannot find suitable LED shops in the US when using Google-search from Germany.

BTW those dews and the flytrap look great. i especialy like that notched sundew (it is Drosera schizandra, right?)

Yes, it's a D. schizandra. Needs very high air humidity in its box.
The other sundew is a Drosera spatulata 'Tamlin'. Needs much less humidity.

i actually have a reef tank (40 g), so i might also want to use LEDs there

In bigger setups you better use fluorescent lights plus optimized reflectors. My biggest LED setup for a small terrarium with pots standing in it is 60 litres, that is 16 US gallons. The more LEDs you use in a lighting setup, the more LEDs become defective. If you read in a LED specification "lifetime 25.000 hours" this doesn't mean that each LED has a lifetime of 25.000 hours, it means that after 25.000 hours half of the LEDs have become defective or lost much of their initial lumens. So you may come to the point if you have installed 10 LEDs that after one year of operation @14 hours lighting period (= 5000 hours in one year) indeed 1 of 10 LEDs have become defective and needs replacement.
 
  • #12
I personally think LED's will be a dead technology for horticultural purposes. The future is plasma fer sure! They're currently WAY too expensive but the pricing will come down in the not-so-distant future. Check this link: http://www.plasma-i.com/lg-plasma.htm Look at the wavelength chart at the bottom of the page. Notice it's more of a curve rather than the "spikey" charts you see for HID, flouro, LED.

And just to let all peeps know I'm not talking out of my hat: I work at an irrigation supply store that dabbles in selling indoor growing supplies for those "tomato" growers here in California.
 
  • #13
I have a friend that is a member of our Aquatic Plant club and he has built a couple of LED fixtures using CREE LED's. He gave a photo step by step on his blog site. Plus there is other information there too. I am going to have him make me one for one of my aquariums. This link is to part 1 of 5 parts. http://aquariums.seaspraydesigns.biz/diy-projects/diy-high-power-led-aquarium-lighting-part-i/

CREE LED's http://www.cree.com/products/xlamp_xml.asp

Heatsinks http://www.heatsinkusa.com/

Cooling Fans http://www.coolerguys.com/

These guys use CREE LED's http://www.stealthgrow.com/index.htm

Here is an interesting site on Inductive Flourescent lightiing. There is even a Youtube video with one of their lamps being powered up under water. http://www.inda-gro.com/
 
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