LED grow lights... input please.

[Gart79]

The really strange thing about plants absorbing only red and blue (purple when mixed), is that there is more yellow and green light out there! Now thatâ??s weird! Our eyes learned to be more sensitive to green and yellow, but plants didn't. Turns out they think that there were actually plants able to absorb all that green and yellow sun light out there, and it was a purple plant! Our plants are only green because red and blue was the only useful light that came through the other plants for the ancestor of our plants (the ones we know and love) to absorb! Weird to think, if things had been different, the world leaders wouldnâ??t be as much concerned with converting to green energy as converting to purple energy.

[manwithbike]

Hey everyone

A friend and I have invested a bit of money on a grow op which includes the xb100 led starter system from GROW WITH LEDsâ?¢ - Growing Plants Using LED Lighting, stealth grow bubbleponics system, and some feminized white widow seeds from marijuana-seeds.nl. We're waiting on the seeds which should be here any day, but we checked out the lights today and they're awesome. I'll keep everyone posted on our results

[Mrs. Greenjeans]

I love stuff like this...new techniques, revolutionary developments. I look forward to reading everyone's experiences.

[RAZ90909]

What would happen if you strobed the led's or used car neon tubes?

[Mista Sparkle]

If LEDs for plants are successful at growing and flowering, they will revolutionize indoor gardening. And I can't wait...

The Eco Green Star Grow Bar has the most attractive overall package. They have information on color, power consumption, recommended growing areas per bar, and more at their website. Each bar is equivalent to 1 250 watt MH or HPS lamp.

Pricing is anywhere from $179 for 1 bar to $1,969.00 for 11 bars.

I would love to try these and stop worrying about ventilation for my cabinet.

[outerspace]

Ive seen some of the led things folks have been putting together over the years and thought I could do better. This is a solid sheet of LED with 660 and 470nm lights the most powerful available in 5mm. I found some better blues at 430nm that are really bright and I should have used those instead. I thought of alot of improvements including a way to achieve 90% power efficiency from the wall socket and a way to adjust the power going into the red or blue lights if you want to 'change seasons.'

Theres just one point I dont think anyone has touched on here yet, is the efficiency of LEDs. They can be around 10-20% efficient, meaning 80-90% of the power you put in is turned into heat, and this is not much better than HPS. More power is wasted into heat as you convert AC to DC, and then even more when you regulate your DC to 20mA.

I heard some folks mention that the high-flux LEDs that require a heatsink are the only ones that work. It takes about 60 discrete 5mm LEDs to equal the luminous flux of 1 high power led. The thing is, 60 discrete LEDs are 1/5 the price of 1 high power LED and thats not including the heatsink. Additionally, high power LEDs have a much lower rated lifespan.

Anyway, let me know what you think. I have not tested it on a plant but I know it kicks the crap out of eco green star and ledgrowlights.com.

[ledfever]

dude outerspace, that is the sweetest led set up i have ever seen. interested in selling one of those light boards? im working on a led/hps flower box (mostly leds and only 250 watt hps) i want to see if i can pull as much if not more than my 600 watt hps in the same enviroment :thumbsup:

let me know ya?

[moeburn]

Theres just one point I dont think anyone has touched on here yet, is the efficiency of LEDs. They can be around 10-20% efficient, meaning 80-90% of the power you put in is turned into heat, and this is not much better than HPS. More power is wasted into heat as you convert AC to DC, and then even more when you regulate your DC to 20mA.

He's right. LEDs are way more efficient than incandescent bulbs, but they're not 100% efficient. Here's the chart:

Luminous efficacy - Wikipedia, the free encyclopedia

An HPS bulb has a luminous efficiency of 22%, while white LEDs have efficiencies from 3.8% to 10.2%, with only prototypes reaching up to 22%.
So, by using LED bulbs for growing, you are spending more money per bulb, and you are going to be spending more money on your electricity bill.

Sounds pretty stupid to me.

[Al B. Fuct]

I heard some folks mention that the high-flux LEDs that require a heatsink are the only ones that work. It takes about 60 discrete 5mm LEDs to equal the luminous flux of 1 high power led. The thing is, 60 discrete LEDs are 1/5 the price of 1 high power LED and thats not including the heatsink. Additionally, high power LEDs have a much lower rated lifespan.

Good points all, but at this moment, ALL LEDs (high-output type which must be heat-sinked or not) are far too expensive, far too inefficient and don't produce near enough luminous output per LED device to be useful in a grow op.

The problem being that luminous output figures (lumens) added together are meaningless. Putting one light source next to another does not make either one any brighter. Lumens are a measure of perceived brightness, not a measure of photons being thrown at your leaves.

For example, if you have CFLs rated at 1300 lumens and you have 50 of them, you then have 50 light sources which are 1300 lumens 'bright,' not 50x 1300 lumens. Same goes for LEDs. The smaller, lower output LEDs, even if run in great numbers, will never be as bright as an LED with a higher luminous output.

Cannabis needs the brightness (or light intensity) to keep internodal lengths short and produce high-density buds. I have yet to see an LED grow that didn't show signs of serious light starvation.

LEDs are a terrific technology; the increases in output and reliability are coming by leaps and bounds in recent years... but it's not quite to the point where you can grow plants with them.

[Al B. Fuct]

Mind you, I don't begrudge anyone the privilege of experimenting with new technologies. No one but us is likely to try the new stuff on cannabis.

However, if one is on a limited budget and just wants to grow some dope with little money or is a very new grower, spending up on re-inventing the wheel via experimental technologies probably isn't for you. Use what is proven to work well.