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My DIY LED build

I've added UV A in the 400nm range for a few years since I have thousands of them laying around. The starts under them do get leggy quickly then when 6" tall and they get topped they explode out the sides.
 
Hello all! 
 
I have doing a lot of research lately for an indoor hydroponics system that I want to build (nft) to grow lettuce, spinach, herbs, and maybe the odd pepper or cherry tomato. I am quite happy that I found this site, as most hydroponic information seems to be found on alternative herb growing websites; its nice to see this tech get applied for much better purposes! 
 
The roadblock in planning my new system has been lighting. It initially seemed like fluorescent (t5/t8) was the best option, but seeing some of the DIY LED builds has made me think otherwise. I have been seeing on a lot of the "other" forums people have been building lights using COBs rather than discrete 1W or 3W modules like this build, and I am a little confused. There seems to be no objective comparison between the two. I have also seen a lot of conflicting information on the lighting requirements, so I am at a loss for how much light output I really need. 
 
My plan is build light bars that cover 4 linear feet x 1' wide each, to cover a total area of 20ft^2. I have been leaning towards building these bars using discrete red/blue/far red 3W modules as it makes sense to only generate the light that the plants require, but people building lights using white COBs tend to say that full spectrum lights create just as much usable PAR. 
 
I am hoping that the OP can share a little more insight as to why he chose discrete colors rather than COBs for his build and how it has performed, but any help or direction would be greatly appreciated, as I am completely lost!
 
I'd answer you but that phrase "much better purposes" irks me.

Scuba_Steve said:
 
Someone correct me if I am wrong, but all my research has informed me that UV light is pointless to most plants.  The major exception to this is pot when it is flowering.  This is why most LED fixtures have UV light.  They are mostly based around the pot market.  IR on the other hand, as someone already mentioned is used to promote the Emerson effect.  Even though this again is not on the normal PAR/photosynthesis spectrum.
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UV is helpful if you're growing something like a red lettuce.
 
eric_pwb said:
Hello all! 
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Welcome to THP! Not all of us are going to throw down with you at the first hint of a political issue. If you'd like to get accquainted, post a thread in the "Welcome" forum, and tell us a bit about yourself. It's a tradition around here.

able eye said:
UV is helpful if you're growing something like a red lettuce.
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This is very interesting. There's a thread about one member's hybrids (CGN 21500 X Isabella Island [Galapagos] Habanero, i think...). He's noted that their growth rate is unusually rapid, and they also have pigmented leaves.

I learned that these pigments were a plant's defense against UV, but i didn't know they were able to use UV as an energy source.
 
mikeg said:
Welcome to THP! Not all of us are going to throw down with you at the first hint of a political issue. If you'd like to get accquainted, post a thread in the "Welcome" forum, and tell us a bit about yourself. It's a tradition around here.

This is very interesting. There's a thread about one member's hybrids (CGN 21500 X Isabella Island [Galapagos] Habanero, i think...). He's noted that their growth rate is unusually rapid, and they also have pigmented leaves.

I learned that these pigments were a plant's defense against UV, but i didn't know they were able to use UV as an energy source.
Click to expand...
 
I would take the unusually rapid part with a grain of salt.
 
But those pigments are used by the human body also. Which is why I said lettuce, something were going to eat and a pepper turns colors regardless.
 
The best reason to include UV is nutrition IMO. And then it would be crop specific.
 
able eye said:
I would take the unusually rapid part with a grain of salt.
 
But those pigments are used by the human body also. Which is why I said lettuce, something were going to eat and a pepper turns colors regardless.
 
The best reason to include UV is nutrition IMO. And then it would be crop specific.
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...so, you're giving red lettuce UV to stimulate an increase in carotenoids and/or anthocyanins (it's mostly carotenoids in red lettuce, isn't it?) because their anti-oxidant properties are a part of good nutrition? That's pretty sound reasoning!

I think you're also right about the carotenoids in peppers. If they reach the colors they do in the shade of their own leaves, the metabolic pathway for carotenoid production doesn't require UV. Besides, the pepper would have an unripe-looking, less-pigmented side -- like an apple of many varieties.

Have you turned up any info about any wavelengths of light that are needed for a pepper to have all the properties of an outdoor specimen? Would any wavelength of light be needed for the production of any essential oil (for example), that is part of the flavor?
 
eric_pwb said:
Hello all! 
 
The roadblock in planning my new system has been lighting. It initially seemed like fluorescent (t5/t8) was the best option, but seeing some of the DIY LED builds has made me think otherwise. I have been seeing on a lot of the "other" forums people have been building lights using COBs rather than discrete 1W or 3W modules like this build, and I am a little confused. There seems to be no objective comparison between the two. I have also seen a lot of conflicting information on the lighting requirements, so I am at a loss for how much light output I really need. 
 
I am hoping that the OP can share a little more insight as to why he chose discrete colors rather than COBs for his build and how it has performed, but any help or direction would be greatly appreciated, as I am completely lost!
Click to expand...
t8s are cheaper upfront.
3w led stars cost less than cob.
i figured matching peaks on par graph is more useful than white alone. Matching peaks + supplementary white is great gives small percentages of all wavelengths. I have 0 research to back this up, you can chose any colors you want. 
output i;m using 1 bar for 1ftx2ftx2ft. you must note that the light penetration is not great, if you have a tall space( say 4' + high) its better to go with an hid probably like the cmh ignite has been using.
 
Thanks for the information everybody!
 
I apologize, I really didn't mean to offend anyone, and I realize that I used a poor choice of words. Overall I appreciate the ingenuity of the people who are growing marijuana, as they really do put a large amount of time and effort into optimizing their techniques, which have a very broad range of applications outside of just cannibis. 
 
Anyway, it seems like from some of the information I have gathered, and the input you people have graciously given me, that lighting using combinations of discrete color diodes maybe the most efficient and cost effective way to go.
 
My initial plan was to use T8 fixtures, but after factoring in their power consumption, efficiency and heat production as opposed to LEDs I started to look elsewhere. At then end of the day, I have been comparing all the information I read to the Phillips GreenPower production modules,  which are Deep Red/Blue strips (36w @ 4') which yield some pretty convincing advantages over T5 (as tested by the lettuce people). 
 
Believe whatever you want that is posted about NM plants need.
I've been using home made 1 watt and less LEDS for years.
 
I only know what works for my grow - Peppers only.
 
People think a LED rated as X nm. puts out only that wavelength.
 
It only means it puts out over 50% of that wave length.
 
Take a CD and look at the rainbow of color you get from any light source and you'll see wide and short bands of color along with Yellow,purple etc.
 
Most of the "YA gotta do this or that stuff on the net is B.S."
 
My plants never got the memo about how bad my LEDS suck...
I use this as a reference.
 
380 - 400 nm Start of visible light spectrum. Process of chlorophyll absorption begins. UV protected plastics ideally block out any light below this range.
 
400 - 520 nm This range includes violet, blue, and green bands. Peak absorption by chlorophyll occurs, and a strong influence on photosynthesis. (promotes vegetative growth)
 
520 - 610 nm This range includes the green, yellow, and orange bands and has less absorption by pigments.
 
610 - 720 nm This is the red band. Large amount of absorption by chlorophyll occurs, and most significant influence on photosynthesis. (promotes flowering and budding) The ratio of red (660nm) to far red (730nm) in sunlight is about 1.2:1
 
720 - 1000 nm There is little absorption by Chlorophyll here, but Phytochrome uses a nice portion. Flowering and germination is influenced. Near and above the higher end of the band is the Infrared spectrum, which can also be heat and could cause elongation or affect water absorption/transpiration.
 
Many of these plant pigments have dual wavelength peaks that can be activated with led light combinations:The visible colors of light from shortest to longest wavelength are: violet, blue, green, yellow, orange, and red. Ultraviolet radiation has a shorter wavelength than the visible violet light. Infrared radiation has a longer wavelength than visible red light. White light is
 
Beta-carotene 450nm 480-485nm dual peak
chlorophyll a 430nm 662nm dual peak
chlorophyll b 453nm 642nm dual peak
phycoerythrin 590nm single peak
phycocyanin 625nm single peak
a mixture of the colors of the visible spectrum. Here is a summary of wavelengths (nm). If you are building your own LED Grow Lights it may be of help when selecting LEDs for your project.
 
200 - 280 nm UVC ultraviolet range which is generally harmful to plants. LEDs in this spectrum are non-existant or very expensive.
 
280 - 315 nm Includes harmful UVB ultraviolet light which causes plants colors to fade. UV LEDs in this range are now available and coming down in price.
 
315 - 380 nm Range of UVA ultraviolet light which is neither harmful nor beneficial to most plants.
Works for me,ALL I grow are peppers.
I had pics of my 5ft. tall X 6ft. wide hydro plant posted a while back.
Lots of pods on that 7 pot sr.
 
I use 1 watt and less LEDS.
 
I use any LED that gives me the wave lengths I want. (400nm - 470nm blue and 625nm - 670nm red.)
 
The in between stuff is probably given in high enough amounts for peppers anyway.
 
I use 1 watt LEDS because I can put a ton more per panel without cooling them.
 
3 watt ones needed too much spacing and thus wouldn't allow me to put overlaping wavelengths evenly over my plants.
 
I also place on my shelves (18in.X4ftX 2ft.)LEDS both vertical and horizontal lights.
 
Nothing like a 4 inch plant branching out with buds when I pot up from my 72 cell starer tray.
I have pods on plants in my 72 cell starter now.
 
No pics anymore.Won't post any these days.
 
Got tired of other people using them as their own or sites keeping them as their own (like this one).
I deleted my photo bucket account but find MY pics online credited to THP or other sites.
 
Most of the "Ya gotta have" stuff is crap for pot or just plain sales talk for light source vendors in my opinion.
 
My plants never got the memo...
 
A lot of people I know use white LEDs instead of fluoros.
 
Some use the 12 volt Halides(blue),car headlight bulbs.
 
They work the same as fluoros but put out more light for the power they use.
 
Too many generalities are taken as fact these days.
 
I use what works for my grow.
I like my 1 watt stars mounted on 1/8in. sheets of aluminum.
 
No cooling needed.
 
The 125,10mm leds on a 11in. x 7in. perf board is what I use to cover the wavelengths stars don't cover get hot at times.
Put out 2X the Lumens than the stars but they work.
 
I know people who use only blue or only red Leds and get pods from their peppers.
Same with people using 6500K LED white spots on their plants.
 
Boils down to believe what you want to.Use what works for your grow.
 
I ignore most "ya gotta do" stuff.My plants for the last 5+ years told me different.
 
Edit since I got a like-
I fried a few 1 watt blues,fried a few more 10mm Leds.
Was my fault,I wanted the NM they gave out at what I was running them at.
I don't think I ever gave how to run things at Other than saying I use the LM regulators.
I think I posted They aren't very efficient too.
I was using LEDs and am from the early days.
Until mine fry,I'll never stop doing what I do.
 
I do think,LEDS in 6500 white in the LM they put out are probably better.
My stuff was built years ago with what was available and cost effective at the time.
 
People are just now understanding reality as far as lighting goes.
Use what YOUR grow and needs.
Nutes,soil etc.
Nothing is set in stone.
 
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