Growing with LED's?????

As far as cons go, No, it's stuff learned by my conversations with Dr. E. R. Myers, a plant biologist, who has grown with every light imaginable. Here's one of the papers he's written for HTG Supply.

http://www.htgsupply.com/images/articles/HTGSupply-Light-Article-August-2008.pdf

Enjoy.

la9 said:

After a foot tall I'd say that the UFO is not producing enough light for the plant and that is the problem. Plus with the LED's being directional and the plant's start getting wider at around a foot tall I could see why growth would be dropping off.

Click to expand...

The reason is that the majority of light intensity, or lumens per square foot, is within the first 12 to 12 inches of light under the LED. But even in that area there is not enough lumens for big bud. So even if you used a growth stopper like Super Bud or Sudden Impact to keep the plant under 2 feet, which would concentrate the maximum intensity of the LED light onto the buds and fan leaves, you are not going to get as much bud as a lighting outputting over twice as many lumens per square foot...as the HPS does.

la9 said:

That's funny saying you don't care when you follow me from thread to thread. It's also funny you say you want to discuss, research and improve growing with LED's yet when I offer such an opportunity you change the subject and run away.

Click to expand...

i said i dont care wat u talk about and i dont follow u thread to thread..we both have interest in LED on whether theyre good or they SUCK as u suggest thats why we both are on the same threads..but if u really want to say who is following, it would be u, remember im pretty sure u were the first to post on my thread..never changed any subject and never ran..im not a moderator for this thread or site so im not gona run what is discussed...

Jonus said:

That is not the reason seedlings or plants in general grow lanky under incandescent lamps. The reason is that they don't predominantly emit red/yellow light as the good doctor has stated, but in fact predominantly emit infrared light, more infrared than any other part of the light spectra, which signals the plants that the lights are off.

After a day or so of using the incandescent, because as the good doctor rightly stated, plants don't have seeing eyes, your plant will begin to search for light, because even though the lights are on, the pigments in the leaves are picking up the majority infrared, tricking them into thinking they're receiving the same signals plants receive when the sun has gone down, or when leaves are in the shade, where there is normally more infrared light than red light, and that is where the stretching comes in.

I wouldn't use LEDs in with an HID for the reason that that would mean placing the LEDs between the HID and your plants. The heat from the HID will cut the life of your LED lamp in half.​

Click to expand...

While yes incandescents output a large amount of IR - a quick look at the spectral chart of an incandescent bulb compared to the sun confirms that incandescents do not put out blue light, which is a requirement for short internode length, as the doctor stated.

As for LEDs with an HID, this is not true if you used the LEDs at the sides of the plant, at an angle. Imagine it like this: HID for center overhead, LED spotlighting around the sides. As long as the LED used supplements the missing end of the spectrum that the HID fails to provide, it would be just fine.

Chart concerning the incandescent spectrum attached.

I think you missed my point. The reason for the massive stretch you get with incandescents is more about the infrared they're outputting than the balance of blue and red. Try it if you get a chance. Set up a side by side grow with a 42w red spectrum bulb growing one plant, and a mix of a 6500k 42w grow bulb and an infrared spotlight to grow the other.

The results will astound you. The plant that was grown under the blue light in theory should have tighter nodes than the one grown under the warm white light, but it won't. It will be about a foot higher than the red spectrum bulb grow after about 2 weeks.

The reason for this is as I stated, the light recepters in the plant think that because there is massive amounts of infrared present, the plant must either be in the shade or the lights must be out so it will stretch to shit to try and find a light source. And the best direction for it to grow toward is where the infrared is coming from.

I agree with what you say about the blue spectra and its affects on tighter nodes, but that is not the primary and overriding reason for the massive stretching plants do under incandescent/tungsten lamps.

Okay, I see what you're saying now.

But I thought the main purpose of IR sensitivity in plants was to know the diurnal change (eg photoperiodism) between night and day so the plant knows when to go from vegetative to generative stage.

KaliKitsune said:

As far as cons go, No, it's stuff learned by my conversations with Dr. E. R. Myers, a plant biologist, who has grown with every light imaginable. Here's one of the papers he's written for HTG Supply.

http://www.htgsupply.com/images/articles/HTGSupply-Light-Article-August-2008.pdf

Enjoy.

Click to expand...

X cept LEDs