LEDs Used for Indoor Farming "Tuned LEDs" - Page 1
Forum section: electronics / projects

author: ADC-1995
author_rank: Regular Contributor
timestamp: December 31, 2015, 04:23:17 am
content: I have heard of indoor agriculture using various methods which usually involves a lot of power from lights. However I came across this article and it was intriguing. They were using specially tuned LEDs and certain LED light wave lengths to turn over crops -" micro-green crop roughly every 12 days, baby greens about every 30 days, and lettuces about every 35 days"Those numbers are impressive, but it had me wondering what are "Specially tuned LEDs". I think that's code for a certain voltage / amp / color and LEDs that may transmit more infrared than others.http://www.popsci.com/farms-grow-up-thanks-to-technologyHas anyone tried this on a small scale or can describe the "Tuned LED" response from the article?

author: Bancroftjo
author_rank: Contributor
timestamp: December 31, 2015, 04:37:46 am
content: I have not tried using these LEDs but it is on my to do list. I believe the "tuning" you are asking about is simply the color of the LED. Recall that photosynthesis uses light, water, and nutrients to synthesize plant food, the reaction depends on certain wavelengths (colors) of light. These LEDs are specifically made to emit the wavelengths needed for these reactions, hence resulting in a more efficient growth system. I believe Phillips is a primary developer of these LEDs, check out the link below.http://www.thelettucepeople.com/product/philips-led-grow-light/Jon

author: nowlan
author_rank: Frequent Contributor
timestamp: December 31, 2015, 05:03:36 am
content: https://en.wikipedia.org/wiki/Photosynthetically_active_radiationLots of interest from marine fish (coral) tanks and weed growers.http://www.advancedaquarist.com/2013/2/equipment

author: SeanB
author_rank: Super Contributor
timestamp: December 31, 2015, 07:06:33 am
content: Basically red and blue leds that are the wavelengths best absorbed by chlorophyll. You simply apply the 2 wavelengths that are needed, so that the chemical reactions occur with the least amount of excess energy which will cause heating. Thus you get the highest conversion of electricity into plant mass.Normally you also use this with hydroponic nutrition, so as to provide the plant with the nutrition it needs without it needing to grow a massive root system, or you use a gravel bed with drip irrigation for the same reason.

author: Fungus
author_rank: Super Contributor
timestamp: December 31, 2015, 10:06:33 am
content: I'm guessing they're referring to the optimal wavelengths for photosynthesis.ie. Shining green light on plants is a complete waste of energy.(Obvious: Leaves are green therefore green light isn't absorbed by leaves...)If you concentrate all your light energy at the wavelengths in the two peaks on that graph then you'll lower your electricity bill significantly.Will it make them grow magically fast? If you put in the same wattage as somebody who uses white lights then yours will definitely grow faster than the other guy's.

author: jdraughn
author_rank: Regular Contributor
timestamp: December 31, 2015, 11:38:12 am
content: The different wave lengths are also for "tuning" what stage of growth the plant is in. In addition to the types of nutrition, watering and temperature the light also helps the plant to grow foliage or flowers or roots.In the fall the wave lengths of light from the sun differ a little which helps signal to the plant that it's time to start seeding (in addition to colder temperatures and shorter days).

author: Jeroen3
author_rank: Super Contributor
timestamp: December 31, 2015, 06:50:32 pm
content: Quote from: Fungus on December 31, 2015, 10:06:33 amCombine that with additional heat and co2 to make it grow fast.I recently was at a plantation for flowers where they got four natural gas generators, one of them I can confirm to be 2MW, the rest is probably identical.Just for the heat, lighting and the co2.They also have very special lighting.

author: Seekonk
author_rank: Super Contributor
timestamp: December 31, 2015, 09:22:49 pm
content: One more.......I used to grow plants with ultrasonics. Faster germination and higher germination rates. Just don't let them grow too long with sound.

author: pickle9000
author_rank: Super Contributor
timestamp: December 31, 2015, 09:51:58 pm
content: LED grow lights are widely used in marijuana grow ops.http://www.ebay.ca/sch/i.html?_odkw=led+medical+flower+plants+200w&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xled+medical+flower+plants+150w.TRS0&_nkw=led+medical+flower+plants+150w&_sacat=0

author: Don Hills
author_rank: Regular Contributor
timestamp: December 31, 2015, 11:09:08 pm
content: An article about led light indoor farming, showing a typical grow rack:http://www.siliconchip.com.au/Issue/2012/March/Vertical+Farms%3A+Factory+Farming+In+The+21st+Century(Preview only, you need to subscribe or buy the article)

author: ADC-1995
author_rank: Regular Contributor
timestamp: December 31, 2015, 11:15:25 pm
content: ]Quote from: Jeroen3 on December 31, 2015, 06:50:32 pmSounds like a nice setup. The co2 is a new angle. It sounds like it can get very in depth to go full scale. In the article, turning veggies at that rate was probably more like what you are describing here with a combination of multiple factors reaching further than lighting, temp, and soil content.Quote from: Fungus on December 31, 2015, 10:06:33 amNice chart on Photosynthetic light spectrum. That confirms the two ends of the spectrum for full growth potential. I also was reading that the higher end, red, has more UV which also contributes to heating the plants which assists in cell growth. BUT, a fine line as to much UV will kill the plant, destroy cells, and dry it out.If anyone knows the part number to these LEDs or a specific name that would be helpful. I wouldnt mind building a circuit and test these LEDs on some cabbage and beans to see if there is much of a difference especially since winter has set in here in the US.

author: ADC-1995
author_rank: Regular Contributor
timestamp: December 31, 2015, 11:20:32 pm
content: Quote from: Don Hills on December 31, 2015, 11:09:08 pmI started the article and "feeding the increasing hordes" was a bit funny. The article looks great so far.

author: RobertBG
author_rank: Regular Contributor
timestamp: January 01, 2016, 12:41:14 am
content: Once upon a time I may or may not have had a room for clandestine gardening to generate income to supplement my college tuition.Back then everything was metal halide and high pressure sodium bulbs,the LED's were just coming out but they had yet to prove themselves and actually performed poorly but today's tech is tenfold what it was then.You could get some growth with CFL's but they just dont penetrate or go the distance.When the LED's first came on the scene,they had all sorts of mixtures of bulbs,even UV etc and as time passed they really started to get them dialed in and the costs have come down to the point that they are affordable and a realistic replacement for MH/HPS lamps.I hate to say it but indoor pot growers have really helped push technology to the point where it is today.The reason we have the CO2 controls available today is because guys originally needed to fight the temps created by the lights and dumping CO2 was how they did it.Now days as a parent I cringe at the growing pot part but if you can get past that there is a guy on youtube that has a video grow diary.He is using both LED's and HPS systems and his plan is to switch over completely.When I first looked into it he had a nice how to video on making them that is worthwhile as he has them setup side by side for comparison and he even used a commercially sold unit.It was one of the few times I saw LE's and HPS setups in the same room and the results were surprising but the pot part can be offensive to some.I actually have a LED light project on my to do list.I eventually want to do a nice little indoor hydro setup with LED's as I think it might actually be worth doing with the efficiency these days.

author: kmm
author_rank: Regular Contributor
timestamp: January 02, 2016, 11:19:58 pm
content: Quote from: SeanB on December 31, 2015, 07:06:33 amI've got a small seedling box and I've been doing some (very) informal experiments with LED lights. I started with a 2 wavelength red/blue off the shelf ~10W grow light (9 chip COB emitter in the typical chinese IP66 floodlamp enclosure). I noticed the plants (tobacco, habanero cultivars, and some of the devil's lettuce [legal in my state]) were living, but not really growing or thriving to any substantial degree. I'd call it stasis more than growth.From there I built my own multi-spectral lamp, from six 3W "star carrier" chips, also driven at 10W. The current lamp includes ~660nm red, ~445nm blue, 505nm aqua, and 4000k and 30000k white. Chips are nothing special, just the cheapest ebay varieties, because that's how I roll. O0There is some evidence that green light contributes to photosynthesis, which is why I added the aqua and white emitters:http://pcp.oxfordjournals.org/content/50/4/684.fullWhile I don't think the balance of spectra I have now is optimal, the performance of this lamp in terms of growth has been night and day, particularly with the tobacco plants, which are quickly outgrowing the box.As I get more grow space set up I plan on experimenting further, right now I only have the one small box so I can't run any comparisons.Based on the difference in growth I observed despite the same overall power, I think there's reason to believe that plants will run on blue+red alone, but some additional spectra will help push photosynthesis along to some degree.Either that or my current configuration is more efficient than the original, and is just putting out much more light of all flavors. I'm not sure since I find it hard to compare narrow band light output to broadband, and don't yet own a light meter. Another future experiment there.

author: Bryan
author_rank: Frequent Contributor
timestamp: January 04, 2016, 10:03:34 am
content: Quote from: kmm on January 02, 2016, 11:19:58 pmWould be interested in seeing a pic of your setup, I have one of those 7 pod Aerogardens. Going to hack it and add my own LED setup to it. I notice the growth of plants dramatically decreases if the light bulbs are not changed every couple months. think the LEDS might offer better growth and certainly a longer lifespan

author: kmm
author_rank: Regular Contributor
timestamp: January 05, 2016, 07:44:11 am
content: Quote from: Bryan on January 04, 2016, 10:03:34 amI will warn you the construction is ghetto and deathtrappy, but I will note the heatsink is properly earthed, with crimp, and the entire assembly is securely affixed to the top of the box with genuine duck brand duck tape.The star carriers are epoxied to the heatsink (an old CPU cooler) with JB-weld, and the power supply is a 10W constant current "brick" cannibalized from the original lamp.I'm running the LEDs series-parallel as two strings of 3 (currently 2x blue, 2x red, 1x aqua, 1x 4000k white). I swap out the chips by desoldering them from the carriers, it's very easy.According to the kill-a-watt it's plugged into, it draws 9.5W from the wall, about same as it did pre-hack; I'm guessing there's around 1.5W getting to each chip, or about 50% of their rated power.The heatsink only gets warm to the touch (maybe 40C), and the epoxy seems to provide a reasonable thermal interface since the carriers and LED packages feel more or less the same as the rest of the heatsink after it's stabilized.Yuuuuge tobacco plants seem to like it, they've pretty much outgrown the enclosure.

author: Bryan
author_rank: Frequent Contributor
timestamp: January 05, 2016, 09:29:01 am
content: Wow, the growth is pretty impressive considering just 6 LEDS's. Likely not using optics allows some of the light to bounce around a little more.

author: RobertBG
author_rank: Regular Contributor
timestamp: January 05, 2016, 03:40:10 pm
content: Quote from: Bryan on January 05, 2016, 09:29:01 amI agree,that is quite impressive.How does the LED's penetration compare to CFL's? and do you have a light meter by chance?

author: picandmix
author_rank: Frequent Contributor
timestamp: January 05, 2016, 05:41:39 pm
content: These look interesting, which match the colour spectrum shown earlier , should save on using different colour leds ...http://www.ebay.co.uk/itm/1W-full-spectrum-400nm-840nm-LED-Bead-Grow-Plant-light-with-20mm-Base-30mil-chip-/371421852164?var=640501752138

author: kmm
author_rank: Regular Contributor
timestamp: January 06, 2016, 01:24:17 am
content: Quote from: RobertBG on January 05, 2016, 03:40:10 pmI remembered my CEM DT-61 multimeter has a light sensor, so I did a quick comparison of my hacked light and a stock 2-band LED grow light identical to the one I replaced.This meter is <$100, has never been calibrated, I have no idea what its wavelength response is, and it's kinda a multimeter bullet point feature gimmick anyway, so take these numbers with a grain of salt. I have popped it open though, and it's reasonably well constructed. I still use it regularly cuz it boots faster than my Fluke 287. =)I'm not sure how penetration is typically measured, do you have any links for future reference?Experimental setup:Multimeter placed on stand in center of grow box approximately level with soil in the pots.Sensor is off-axis from the light center by approximately 3cm, and the light is approximately 15cm from the sensor.Meter reading is observed through a hole in the lid.Unmodified grow light, 10W, 2-band (2:1 red/blue ratio): 7.9W draw, 1926 luxGhetto fabulous yolo swag 6 LED multiband: 9W draw, 3155 luxSo my lamp is either putting out 39% more light for 12% more power, the sensor is reading mine higher due to its response curve, or perhaps most likely a combination of both.I'm not sure if the power consumption difference is just variance between bricks, temperature (hacked was warmed up to around 40C, unmodified was straight out of the basement at ~19C), LEDs used, or something else; hypothetically both power bricks are identical.The COB 2-band LED is arranged as 2 columns of 3x red chips, and 1 of 3x blue chips in a 3x3 series/parallel array, mine is 3x2 series/parallel.Does anyone have a recommendation for a proper light meter (ideally one that can sanely deal with narrow/wideband comparisons, not sure if that's common on the low end) in the <$100 range?

author: timofonic
author_rank: Frequent Contributor
timestamp: January 07, 2016, 12:20:52 am
content: Quote from: kmm on January 06, 2016, 01:24:17 amLight is one of the topics that interest me a lot. I wonder if it's possible to develop a decently good DIY light meter (light spectometer? What's the name?) to compare that stuff and even measure light propagation over a room or an enclosure.This would be very helpful to make my future UV PCB exposure box and replace my bulbs with LEDs.About pot haters:What do you think of alcohol?Lots of people dead because of alcoholism, but it's very rare you get dead with the funny lettuce. Only if you have a severe mental illness like schizophrenia, but that can happen you with alcohol or any other drug.I agree being a "pothead" isn't good for anyone, you are a dumbass that cares about nothing. But if using it properly, it has very therapeutic uses and has less secondary symptoms than the loved Valium, morphine & derivatives. This is very interesting from glaucoma, cancer or extreme anxiety issues.Even some governments are starting to legalize it.Did you know historically alcohol got used mostly because it's preservation effect and the "funny effect" was caused by the added herbs?

author: Fungus
author_rank: Super Contributor
timestamp: January 07, 2016, 12:42:46 am
content: Quote from: timofonic on January 07, 2016, 12:20:52 amGoogle for "DIY spectrometer" gives a lot of results.Quote from: timofonic on January 07, 2016, 12:20:52 amMy mother, my sister...Quote from: timofonic on January 07, 2016, 12:20:52 amThe problem I have with pot is that it appears to negatively alter young/teenage brains.And theoneproblem I have with drug use in general is that people drive cars after using them.(I think good roadside tests for THC/opiates are starting to appear, they can't appear too soon IMHO).But apart from that; legalize the hell out of them, yes. The reduction in drug-related crime alone would be worth it. Put the cartels out of business.I don't partake myself but what people do in their own home is thier business.

author: ADC-1995
author_rank: Regular Contributor
timestamp: January 14, 2016, 06:39:13 pm
content: Quote from: kmm on January 05, 2016, 07:44:11 amNice! Proof of concept.Looks great, nice idea for capturing moisture. How old are the plants in the picture?

author: ADC-1995
author_rank: Regular Contributor
timestamp: January 14, 2016, 06:48:09 pm
content: Sorry about the confusion on this post. Smart devices can good and handy but when you have a small display and trying to quote and post it does not always work out.Ladies & Gentlemen. Please keep this subject on topic. I am not trying to offend, but I don't want to have this discussion turn into a political discussion about legal or illegal activity, debate over drugs, who is right or wrong. These issues can go round-n-round until you are blue in the face. It would be greatly appreciated.Thanks!

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2016, 04:03:21 pm
content: ADC-1995, can you please fix your post formatting? I think you left several unwanted opening quote tags, such that everything is misattributed.

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2016, 04:10:31 pm
content: Quote from: timofonic on January 07, 2016, 12:20:52 amSay 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?!?

author: ADC-1995
author_rank: Regular Contributor
timestamp: January 16, 2016, 06:10:10 pm
content: 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=1668KMM- 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.

author: jolshefsky
author_rank: Regular Contributor
timestamp: January 16, 2016, 08:13:13 pm
content: 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.

author: chris_leyson
author_rank: Super Contributor
timestamp: January 17, 2016, 11:54:56 pm
content: These LED panels are not safe,https://www.eevblog.com/forum/chat/well-that's-not-safe/msg843977/#msg843977110V 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 hydroponicdeathraystunguns guys.I would be interested to see if the LEDs work though