LEDs Used for Indoor Farming "Tuned LEDs"

[tooki]

Did you know historically alcohol got used mostly because it's preservation effect and the "funny effect" was caused by the added herbs?

Say what now? Humans have been fermenting alcoholic beverages on purpose for around 12000 years. Before that, the intoxicating effect of alcohol was likely known from fermented fruit (as many animals do).  Distillation is a much, much newer discovery.

And are you saying alcohol alone isn't intoxicating?!?

[ADC-1995]

I reviewed the wave length values for the red and blue LEDs on different products and they appear to be  focused on certain wavelengths. And the lights for plant growth seem to be. I was looking for aquas and yellow and there are not very many available in the star design. The following article reviews why this maybe the case. It appears that due to the pigment color of green in plants, that wave length is not as important and is does not absorbed as easily due to evolution. This quote from the article sums it up well:

" The pigment responsible for most light-harvesting by plants is chlorophyll, a green pigment. The green color indicates that it is absorbing all the non-green light-- the blues (~425-450 nm), the reds and yellows (600-700 nm). Red and yellow light is longer wavelength, lower energy light, while the blue light is higher energy. In between the two is green light (~500-550 nm). It seems strange that plants would harvest the lower energy red light instead of the higher energy green light, unless you consider that, like all life, plants first evolved in the ocean. Sea water quickly absorbs the high-energy blue and green light, so that only the lower energy, longer wavelength red light can penetrate into the ocean. Since early plants and still most plant-life today, lived in the ocean, optimizing their pigments to absorb the reds and yellows that were present in ocean water was most effective. While the ability to capture the highest energy blue light was retained, the inability to harvest green light appears to be a consequence of the need to be able to absorb the lower energy of red light."

http://scienceline.ucsb.edu/getkey.php?key=1668

KMM- You have one other plant outside the grow box to the left that appears to like your light setup also.  It is really stretching out there.

[jolshefsky]

I did a little research on LEDs for my own indoor growing setup. I ended up going with 4 T8 bulbs: two warm-white and two cool-white.

The wavelength information wasn't particularly convincing to me. If I remember right, there was a lot of anecdotal evidence that red and blue worked great, but more intensive and objective studies didn't show as good a plant health.

The other thing was the sheer intensity of light you need. The 4 T8 bulbs I have are 32 watts each and emit about 2,900 lumens (90 lm/watt). The total 11,000 lumens was at the very minimal light needed for the 6'x1' (~2m^2) area for the plants.

I thought it would be really neat to have LEDs, but I just couldn't justify the added cost for such a basic, amateur setup. Plus, the white light adds to the room light whereas a blue/red LED setup would not. The bulbs I bought were rated for 30,000 hours, and considering I've got them on a timer for 14-hour days, I expect them to live up to their rating.

If you're not an agriculture expert, the amount of information is daunting. I went for the crudest setup—one that simulates sunlight as best I could for a long day. But red makes some plants bushy, and blue makes some plants flower, and some plants like short days, and some plants fruit on long days—it's really quite overwhelming.

[chris_leyson]

These LED panels are not safe, https://www.eevblog.com/forum/chat/well-that's-not-safe/msg843977/#msg843977
110V peak string voltage on exposed PCB contacts. Ouch. 106 LEDs in total so probably 53 of those are red or blue. At say 2V per led that's about 110V per string. Not even safe if you isolate it. Maybe that LED panel was designed for another product and someone came up with a way of recycling things. Dont buy these hydroponic deathray stunguns guys.

I would be interested to see if the LEDs work though