LED's for growing seedlings?

I didn't know of a proper place to post this, heck probably not even in the right forum, but I wanted the expertise of some of the more knowledgeable than I about using LED's as grow lights. The little I've heard I read from a plant forum but they arent experienced with LED's per se just HID or Fluorescent or HPF? lighting.

I was wondering if I can set an array of multi LED flashlights 4-6" away from 2 or 3 small containers surrounded in a white box to reflect the light around it and add a few red LED's from a couple Energizer headlamps for good measure. I read the proper wavelengths of light they need, but how do you determine what each flashlight puts out. All I know is the Lumens approx output.

From another forum:

"You don't need reflectors for LEDs, they are already very directional. You are always welcome to try new things. Your best bet is to wire up an array of deep red ultrabright LEDs (look for 690 or 680 nm), mix in a few blue 420nm to keep the plants sharp and away you go. Or you could experiment with different colours but it seems fairly certain that this is the best combo. Don't try to run it off batteries, you'll want several watts to light even a small flat of seedlings and you want to run them for 12-14 hours a day. You can get 100mW ultrabrights for 50c or so, maybe less now, and an array of 50-100 is a good starting point. Try growing some lettuce or petunia and see how it goes."

i wouldnt. the things have little to no UV, the spectrums are tight, very tight, and the output is not so high (this week) making the cost high.

hid or florescent would be much better choices in this situation.
although the directionality of a led is much better (minus the flashlight they might be stuck in)
a good reflector on hid or florescent, or even shiney side of aluminum foil properly applied will get the light sent back to its destination.
look at most of the cheap lights you can get in fixtures, and they only have white reflectors. change them for "chrome" or mirror type of reflections and get your 180*. with florescent bulbs make sure the reflective material is not to close to the bulb, because the light headed BACK into the bulb is not usefull light, it does not re-triger phosphors, and is blocked by the frosting to much.
fixing what is wrong with the normal hid or florescent FIXTURES would be my choice for indoor growing.

i have tried growin indoors, and the plants always cried for light, it was so bad, i could have made any type of greenhouse, and even paid to heat it in the winter, vrses taking them away from the sun.
You would need 1/2 as much power of LEDs as you would Incadescent light, and it would have to have full specturms to have normalcy. sure they like specific light types, but they are still organic not machines.

without enough light, the poor seedlings grow to high
without Moving light they dont aquire normal strength
without spectrum, they change in height or shape, but i think that is mostly due to lack of total ability for photosynthisis.
they really need all the advantages of the sun.

on the other hand, the lenght of time they could stay operational would be an advantage, and the efficiency is almost as good as florescent when point source light.

if they are in a less heated area use hid, otherwise use tons of florescent.

As I recall NASA has been growing plants in space using red and blue LEDs. Surprisingly, it seems that not a lot of UV is required for successful growth. A couple of related links found with google:

http://www.goarticles.com/cgi-bin/showa.cgi?C=40280

How Light Colour Influences Plant Growth

Blue light: plants react to the intensity of blue light. Lessening the blue light will cause poor growth - the strength of the radiation in any other part of the spectrum is not as important as the intensity of the blue, which shapes height and quality.

Red (660 nm) and infrared (730 nm) (also known as IR or far red) light: Intensifying the total of IR in relation with 660 nm red makes plants grow tall and thin. On the other hand if red is increased while IR diminished, plants will be short but thick. Plant reactions are not linear with the red/far red ratio and they can also vary in their response to red and far red light.

Ultraviolet light (UV): While overexposure is dangerous, small amounts of UV light can be beneficial for the flora. In many cases UV light is a very important cause for colours, taste and aroma. But UV-C and UV-B are believed to stop plant spread and this is why they have to be removed from the light under which plants are developed in green houses by UV stabilisers or glass. Removal of the UV up to 400nm is might be effective also in case of virus carrier insects (as insects see partly in UV).

Direct light from the Sun distributes the useful wavelengths only on special times of the day and in small quantum enough for a harmonious growth in some parts of the Earth, yet not enough on others.

Click to expand...

http://www.associatedcontent.com/content.cfm?content_type=article&content_type_id=5914&page=1

http://www.growwithleds.com/

I'm in the process of, among other things, building a large array for a 120G planted aquarium I have. Here in maine power costs $0.15 per KWH, and there's nothing like building your own fixtures.

I just placed an order from besthongkong's ebay store: www.besthongkong.com
http://stores.ebay.com/BestHongKong_W0QQssPageNameZstrkQ3amefsQ3amesstQQtZkm

for a bunch of LEDs ranging in the spectrum. I'm planning on building a pair of arrays 16"x29" for the aquarium, with a handful of white LEDs (just to light up the tank nicely) a handful of blue and red LEDs (hopefully for plant growth) and a range of LEDs in-between to try to balance the coloring of the tank (after all, it's for looking at)

I've used a LED light source to induce photosynthesis in leaves. So, yeah, I think it's possible. I never looked into the wavelengths involved (couldn't care less back when), but check the info here (that's the system I used). The company is very responsive to tech support requests (at least if you have one of their machines ), so chances are you might be able to find the exact wavelengths they use, and then trace appropriate LED's from there.

I did a rough back of the envelope calculation years ago, and it does seem feasible to use LEDs as growlights. I haven't recalculated in a while to take into account brighter & cheaper LEDs, but the conclusion I had was that LED growlights were feasible for small setups (i.e. a few plants, like 3 sq. feet or less). Once you start getting into larger setups, the HID and fluorescent lights became a lot more attractive in price. But that was mostly because blue LEDs were a lot more expensive a few years ago, and I'm too lazy to make large arrays of LEDs.

Just taking a quick look at the prices of the LED growlights at growwithleds and prices of HID/fluorescent setups, [pre-made] LED growlights are still significantly more expensive. You could of course impress all your friends and save a lot of money by building yourself...

Thanks for the link at growwithleds.com. Looks promising. $300 isn't a bad deal for a small setup. The savings in energy costs will start paying for itself in a few months.

That said, with more and more interest in LED useage, price will come down. I would think a year for now there might be more interest to cut that $300 down to $175 for pre-built arrays.

I really dont see LEDs being good for seeds or plants.
Very very very little usable "light" to a plant. Compared to incan at least.
Not saying they wont do anything, but the wavelength just isnt there.

Some nice plant Flourescnets would be better I bet.
Metal Hilyde would do really well.

~John

Yeah! And LED's keeps the DEA from finding your house through excessive power usage either...

LOL!

LOL!

The idea that plants need UV appears to be a persistent urban legend. "Full spectrum" (read: expensive) lamps are also overrated. What plants need are the red and blue wavelengths. That's why fluorescent grow lights have those strange blue-pinkish phosphors. It's ugly to the human eye, but plants love it.

I've grown plants indoors using only cool-white fluorescent tubes, or an equal mixture of cool-white and blue-pinkish plant tubes. People have a tendency to use too little light, and quantity is more important than quality. Also, a fixture with a more expensive, higher output ballast is worth paying for.

Right now, fluorescent is a better choice than LED due to advantages in efficiency and area coverage. If you need more intensity, go with metal halide.

robiewp said:

As I recall NASA has been growing plants in space using red and blue LEDs. Surprisingly, it seems that not a lot of UV is required for successful growth. A couple of related links found with google:

http://www.goarticles.com/cgi-bin/showa.cgi?C=40280


http://www.growwithleds.com/

Click to expand...

Thanks for the links robiewp, I noticed a link at the growwithleds.com site to a UofM study in PDF form:
http://webzoom.freewebs.com/growmidwestled/UofMStudy.pdf
...which was worth looking at.

And robiewp, please keep us posted on your project with the "besthongkong" LEDs. Sounds interesting.

Kenski

AJ_Dual said:

Yeah! And LED's keeps the DEA from finding your house through excessive power usage either...

LOL!

Click to expand...

Ha! You know, the thought that was going through my head was "here comes the regulation." Just as soon as some 'plant growth technician' figures out that he can start using LED's to fly under the BATFE radar, the BATFE may start unhatching all kinds of interesting legislation to control the purchase and distribution of LED's capable of causing plant growth.

They've done it/are trying to do it with many over-the-counter meds, and they are constantly looking to do it with other chemicals. One of my hobbies uses a lot of lye (which is also, evidently, used in meth manufacture) and I've seen the difficulty in obtaining it grow continuously harder. Red Devil has even stopped the manufacture of the powdered lye, claiming slow sales, but more likely due to pressure.

BUT, I will tell you that the 'shower head' lights might finally find their niche in all of this: growing 'chronic.' Flood pattern good. :naughty:

My investigation shows that they are by far not the best option for photosynthesis. Primary photosynthesis (the plant uses chlorophyll) needs light of 350-450nm wavelength (with a peak at about 430), and 640-680nm (with a peak at about 670). Secondary photosynthesis (the plant uses carotenoid) needs light in the 375-500nm wavelength (with two peaks, one at 455 and one at 475).

So obviously you need lots of light in the 350 to 500 nm range. While LEDs cover this range, their light emissions don't line up with the peaks required by plants - meaning they aren't going to be very efficient.

I agree with others - HID (metal halides) or fluorescent lights are the best option. HID lights have come down a lot in price recently, try a hydroponics shop, or a aquarium supply shop.

Good luck, if you do get an LED array to work as well as HID then it will be a good achievement.

AJ_Dual said:

Yeah! And LED's keeps the DEA from finding your house through excessive power usage either...

LOL!

Click to expand...

You got that one right. LED to grow THC.

AJ_Dual said:

Yeah! And LED's keeps the DEA from finding your house through excessive power usage either...

LOL!

Click to expand...

Fat chance. LED's are much less efficient than Fluorescents (typically 80lm/watt), Compact Fluorescents (typical 65lm/watt), or HID (typically 100 lm/watt). LED's look good in large part because low wattage incandescents are so BAD...

Even a 10 watt HID is 50 lm/watt. That is beyond the top of even the legendary X bin Lux-V that nobody has ever seen....

Apparently red LEDs are 60% more efficient than fluorescent light when growing vegetables hydroponically.

Cosmo's customers uses the technology to produce 7000 heads of lettuce per day all year round in a 10-floor building on just 1000 square meters of space. The lettuce matures more than three times as fast under the LEDs than outdoors.

http://www.gotoreviews.com/archives/hydroponics/red-leds-to-grow-lettuce.html

mattheww50 said:

Fat chance. LED's are much less efficient than Fluorescents (typically 80lm/watt), Compact Fluorescents (typical 65lm/watt), or HID (typically 100 lm/watt). LED's look good in large part because low wattage incandescents are so BAD...

Even a 10 watt HID is 50 lm/watt. That is beyond the top of even the legendary X bin Lux-V that nobody has ever seen....

Click to expand...

So mattheww50,

HIDs waste *alot* of energy in spectral output that is not needed. So do Fluorescents and Compact Fluorescents.

And a 10 watt HID is not 50lm/W, most especially that Welch-Allyn bulb/ballast assembly which is common around here lately. Once you include the ballast it drops to 38 lm/W, and if you include the reflector it gets alot worse.
Toss out the un-used spectrum, that is not needed for growning lettuce, and things get even worse yet.

Many LEDs are directional, and don't need to suffer the reflector losses of HID.

NewBie said:

Apparently red LEDs are 60% more efficient than fluorescent light when growing vegetables hydroponically.

Cosmo's customers uses the technology to produce 7000 heads of lettuce per day all year round in a 10-floor building on just 1000 square meters of space. The lettuce matures more than three times as fast under the LEDs than outdoors.

http://www.gotoreviews.com/archives/hydroponics/red-leds-to-grow-lettuce.html








So mattheww50,

HIDs waste *alot* of energy in spectral output that is not needed. So do Fluorescents and Compact Fluorescents.

And a 10 watt HID is not 50lm/W, most especially that Welch-Allyn bulb/ballast assembly which is common around here lately. Once you include the ballast it drops to 38 lm/W, and if you include the reflector it gets alot worse.
Toss out the un-used spectrum, that is not needed for growning lettuce, and things get even worse yet.

Many LEDs are directional, and don't need to suffer the reflector losses of HID.

Click to expand...

There is however nothing that prevents a vendor from building either a CF or regular Fluoro using a phosphor mix optimized for the desired wave lengths. Such a lamp would leave the LED sources in the dust.

everyone say it with me "GROW OP"

It would be interesting to see fluorescents that had phosphor mixes tailored to certain types of plants.

do a little research on what leds mitsubishi uses in their photosynthesis inducing fridges, might be of some help.