Led lamp test! 1 week!

[cdamarco]

I think i shall purchase a 90 watt all blue ufo to test on bhut jolokia sprouts, whatever i try i will post what happens 

[CyberDog]

Don't go all blue. Plants require blue and red. I'd choose at least tri-band...

[cdamarco]

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250510022328&ssPageName=STRK:MEWNX:IT
This one look good? I have been looking for a 90 watt ufo similar to yours fatali but this was the cheapest I could find. I felt a bit more comfortable buying from an american seller but i dont know much about led quality really...

[Fatalii]

Well, it's impossible to tell about the picture, when you turn it on, you can easily tell if it uses "spot leds" or not.
Unfortenately, usually the price tells which kind of leds it uses. The prices for the quality leds will run down very quickly. Just good to keep in mind that cheaper lights to use is much more important factor than the price of the lamp itself.

Saving money with low quality led lamp isn't a good option in my opinion...

[cdamarco]

well it says .97 pf in the specs so i assumed it was quality but ya, il see what it can do when it gets here
on a side note, the 14 watt led seems to be doing alright for my bhut jolokia seedlings as a supplement. since i live in an apartment facing north, with a hill in the way as well, my window gets very little light and i have too many chiles to care for anyway at home, hopefully what I cannot fit on the window will get adequate light from this 90w ufo

[Fatalii]

I guess they all are suitable for seedling growing (depending on the spectrum) but the flowering and fruiting will show you what it is really capable of.
Hope it does well!

[cdamarco]

Heh well ebay works both ways, in the likelihood that I get bad apples I could simply resell the lights at roughly the same price 

[Fatalii]

That's true, you can try it

It's sad, but some people are judging leds because of the results they get with poor leds...

[cdamarco]

alright it's finally here and it is brighter than the sun! I have high hopes and Ill be taking photos daily, Ill post the results 

[cdamarco]

It would be interesting to know which wavelength the light of those LEDs have.
It should be about of 460nm for growing and about 630-660nm for flowering. It is said this wavelengths are optimal for plants.
LEDs with other wavelengths of the light would have little to no effect, even if power LEDs!

Emitters should provide light at 460nm, 630nm & 660nm. Most likely they use the same emitter mix in this LED like the others. 20% 460nm, 40% 630nm & 40nm 660nm.

630nm emitters are cheaper than 660nm emitters.

This one should have 1W emitters, 90pcs of them.
Source: http://www.viherpeukku.fi/catalog/product_info.php?cPath=79_172&products_id=791

http://members.misty.com/don/led.html#dr
http://en.wikipedia.org/wiki/File:Par_action_spectrum.gif
Based on what this says, I would think a small deviation from the absorption peaks would be alright if the light output is so many times greater. If deeper red(660nm) led bulbs optimally only produce a fourth the quantity of light(15 lumens/watt) and are at 78% light absorption then I would think simple algebra would indicate that a light at 630 nm that produce 4 times as much light(~50 lumens/watt) at roughly 50% light absorption would be far more productive.
0.78*15=11.7 lumens/watt absorbed
0.50*50=25 lumens/watt absorbed
Chlorophyll b, chlorophyll a and the carotenoids are all associated with the same p680 and p700 enzyme and will all pass on electrons, so photosynthesis will occur regardless of the plant pigment being used, and a plant will produce pigments that match the color of light it is exposed to. In this way they are able to adapt to the light spectra available to become as efficient as possible(to a point). Lights that produce 630nm light are more favorable for chlorophyll b, chlorophyll a likes 660nm light. Chlorophyll a is roughly 3 times more common in plants grown under normal sunlight, but growing a plant under different light (like an led growlight ) would change this proportion of chlorophyll a and chlorophyll b
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC396637/?tool=pubmed
^^This basically says that plants grown under darker light conditions will produce more chlorophyll b in response
Therefore, I think sometimes being cheaper can sometimes be smarter 

[Fatalii]

Well, I still think it is smarter to actually try the lamp at first and then judge it.

Not just how it grows but produces yield too.
At least for me, that's what matters, not just the fancy theories.

[cdamarco]

http://www.youtube.com/watch?v=Fh9oGroryoc
this video claims the 630 nm red led to actually be better than the 660 nm red based on tomato plant yield

[Fatalii]

Nice video which shows nicely how well LED lamp can actually do!

[cdamarco]

http://www.youtube.com/watch?v=dQcV9uya-2Q
another nice video, but at the rate the peppers grow in this I doubt they're just using the 90 watt model

[keto]

Quite interesting that they claim 630nm is better than 660nm, as all other sources I've come across say just the opposite. They also seem to suggest that 1 x 90 W is better than 2 x 90 W...?? 

[cdamarco]

I don't understand it either, I come up with theories but I really don't know, but the 90 w I am using uses the 630 nm and it's doing a fairly good job so I am wondering if all that emphasis on the correct wavelength of red is really overstated or not.

[zenit]

the problem with those videos is that both video posters are light sellers. It is totally not surprising that the model they sell does the best. Alot of these comparisons are bad - they almost never mention if they use identical plants (clones) and comparing growth of 2 or 3 tomatoes will not give anybody a statistically significant effect. Also in these comparisons nobody ever measures biomass (including roots), instead they just go and say "oh look how big my plant is, our light is best evarrrrr".

I am myself trying to grow some chiles from seeds this winter using a Chinese UFO 90W tri-band 660/460/warm white and will add a 65-70W high power LED lamp made with top shelf Osram LEDs (625/455/cool white). So far under the UFO the seedlings are doing great and growing very stocky with very thick stems. LEDs are definately coool.

[Fatalii]

Yeah, to see if they actually work in reality, there's no way around it. The specs won't tell you anything.
The plants will.

Gladly the prices will go down very quickly, just keep in mind the actual price by using artificial light will be the electricity bill so it's not always the best idea to get cheapest lamp.
Lamp which will cost a little more and give better results is actually cheaper in the long run if compared to efficiency, and the lamps are for growing so the yield will tell, right?

Bad yield in a long run with a cheap led lamp.... that's actually a waste of electricity.

But still, the prices are coming down, just don't expect them to be cheaper than HPS just yet.
They have all the reason to cost a little more.

[zenit]

here are pics of my plants under LEDs:



I started them off under t5 24" flourescent tube and moved them under LEDs when they had a pair of real leaves going. So far the experiment seems to be going okay, although I fully expect these plants to suddenly die.

Naga Morrich (3 weeks under LEDs):




Siberian Home Pepper (heirloom?):

[zenit]

Manzano Amarillo: