LED lighting requirements for microgreens and aromatic herbs

Dear all,

I'm about to start an aquaponic project indoors, for those unfamiliar with, it is a mix of hydroponic and aquaculture. I will be growing microgreens and aromatic herbs mainly, the light requirements for these plants are not comparable with cannabis, so I'm hoping to find something cheaper to buy and run instead of HPS or expensive LEDs. I'm also trying to avoid CLF or T5 because of the heat, poor efficiency and need to replace lamps frequently.

I will be growing on a rack of 3fx1f shelves, 3/4f apart. This is the main reason why I'm concerned about the heat of T5. Plus, it won't be possible to hang a single powerful focus of light on each shelf, instead I will need to disperse the light.
It will be something like this:



I ended on ebay looking for cheap LEDs, I know there's some controversy in this forum about them suitability for growing, but let's be pragmatic instead of discarding it that easily.

I found this for 6$ each:



It has mixed blue and red light (nm not specified), 80lum/per watt. This one in particular has 7w, so 560l in total.
I'm planning to distribute 500l per sq ft, so my thinking is 3 of these per shelf (3 sq ft) would do the job.

Upfront cost would be 18$, consumption 21w, 1680 lumens.

Comparing to a 21w T5 , I would end with the same lumens but the upfront cost would be higher since I would have to buy the ballast and shipping costs are also much higher, plus it would be necessary to replace it frequently. Also, generates more heat.

I must say that I plan to distribute 500l/sq ft considering my previous experiences but feel free to contradict me.

Other option is this:


5pcs 15W 36SMD 5050 Red+Blue Grow LED Light for 15$

Voltage: DC12V
LED: red and blue:9 blue,27red
LED Wavelength Red: 660nm; Blue:445nm
Lum/ per watts is not specified

Any idea what does 36SMD 5050 mean?
Consumption is 15W, I still don't know if it per strip or per 5pcs.

This would be the perfect scenario as it is easier to install and assure light is spread uniformly over the shelf.

I would like to know, from anyone who tried these cheap LEDs if it suitable to grow smaller plants in general, herbs, small vegetables etc. I'm sure this wouldn't work for cannabis at all but that is not the point.

Any advice, tips?

Thanks for your time.

Have you considered COBs?

How much experience do you have with wiring and electricity?

I would say that because your not trying to grow quality cannabis but instead other, less demanding herbs and greens, that you will need less given output (watt per square foot) but indeed similar quality LEDs/COBs to ensure a lucrative outcome.

Off the top of my head, Vero 10s and 13s come to mind as a potential possibility in your scenario.

http://www.homedepot.com/p/Philips-InstantFit-4-ft-T8-32-Watt-Cool-White-4000K-Linear-LED-Light-Bulb-434605/205041684

found at your local HD(easy warranty replacement if needed), 110lm/w, fits modern(rapid/instastart ballast) 4ft t8 fixtures.

I've also got a herb project in mind. How much light per area for herbs?

Thanks for passing by guys.

AquariusPanta said:

Have you considered COBs?

How much experience do you have with wiring and electricity?

I would say that because your not trying to grow quality cannabis but instead other, less demanding herbs and greens, that you will need less given output (watt per square foot) but indeed similar quality LEDs/COBs to ensure a lucrative outcome.

Off the top of my head, Vero 10s and 13s come to mind as a potential possibility in your scenario.

Click to expand...

I have basic understanding on electricity and can use a soldering iron.
You asked me if I considered COBs and as result a did some search on the subject. On ebay I found 1w/3w/10W bridgelux and epiled chips for 10$/12$/50$ a pack of 10 units.
Let's say I had 10 of those 3w LEDs spread evenly on each shelf. Doing the math and having in mind each LED produces 240 lumens I would end with 800 lumens per sq ft. To the pack of 3W LEDs add more 10$ for the driver, 22$ per shelf (3sq ft).

Now, there's something I still don't get, why do some chips have the color specifications in nm and others in kelvins? I was looking for something around 420nm-460nm and 620nm-660nm but then I saw these Bridgelux 45mil chips with "cool white" and "warm white", that's when I got confused. Also, I'm little confused about the powering. Enlighten me please

The Vero 10 you advised are very expensive. I don't discard it yet, but first need to get better understanding on this need world of LED lightning.

PSUAGRO. I don't have the ballast, add that cost to the lamp. I need a cheap solution, I don't want to invest too much money in lightning until this technology gets cheaper and better for growing.


alesh, I was thinking of 500 lumens per sq ft for small herbs, but basil for example might require more light so I will be prepared to double or triple lightning for particular plants if necessary. Once everything is running, a couple of weeks will be enough to figure it out and do adjustments if necessary.

Cheers!

I'm thinking for you usage, anywhere between 15-30 watts per square foot would suffice (of quality light).

COBs will provide an array of spectra (400~700nm), while LEDs will only provide specific spectras, such as 660nm or 440nm.

This is partly why COBs cost more than LEDs, because they cover more ground in terms of the plant's needs.

If you order from Ebay or Alibaba, you may or may not come across credible sellers/distributors. Because of this, I advise purchasing COBs from trusty companies such as digikey or mouser.

The start up cost may be intimidating but in the long run, you will be better off.

I understand what you are saying, but than I wonder, if COBs differ only as cool or warm light why do the majority of expensive LED lightning systems have purple light? I suppose they are made of SMD with blue and red mixed LEDs? If so, why don't they use COBs as well?

What should I look for on a COB? Higher CRI is better? Why there are so many different versions of the same model of chip?

Sorry for all these questions, this is all new for me and I don't even to know where to start. It gets even more complicated when I find contradictory information every time I get in a new website.

Narrow band emitters (single color leds) will be specified in nm (wavelength in nanometers), but wide band emitters (white leds) are based on what a hot piece of carbon looks like at a given temperature.


White led's spectrum actually looks like this: (red 3000k, green 4000k, blue 5000k)

Metacanna said:

Thanks for passing by guys.
"why do some chips have the color specifications in nm and others in kelvins?

Click to expand...

Higher CRI just means the spectrum is more even throughout 400nm-700nm, so that color renders properly. (color rendering index).

the higher CRI versions of the same color temperature is generally a lot less efficient than the same color temperatures low CRI version. Most people here would agree that the 5000k 70cri and 3000k 80cri are the best cri options.

Also, the vero line is more expensive, but also has a lot higher efficiency, so it could be worth it if you're trying to save electricity. Then cxa3070 AB bin is even more expensive, but even more efficient. To make matters worse, they all run more efficiently when driven soft, meaning if you want efficiency, you need twice as many driven at half the power!

Metacanna said:

I understand what you are saying, but than I wonder, if COBs differ only as cool or warm light why do the majority of expensive LED lightning systems have purple light? I suppose they are made of SMD with blue and red mixed LEDs? If so, why don't they use COBs as well?

What should I look for on a COB? Higher CRI is better? Why there are so many different versions of the same model of chip?

Sorry for all these questions, this is all new for me and I don't even to know where to start. It gets even more complicated when I find contradictory information every time I get in a new website.

Click to expand...

churchhaze,
Thanks for making it clear about the nm / kelvins. Still I wonder, why manufacturers of expensive LED lightning systems are not using white LEDs. Plants are particular sensitivity to particular wavelengths in order to absorb chlorophyll, so wouldn't it be more efficient to run a 640-660nm LED rather than a 3000k LED? The plants would get more useful light with the first, while the 3000K emits useless green light, so less efficient.
Any thoughts about this?

Ok, so lower CRI is better. This one was easy
Just curious, why is 3000K preferred over 2700K?

Yes I saw the spreadsheet of some chips and noticed that the efficiency drops as you put more current on them. Taking Vero 10 for instance, it gives infinite possibilities of configuration, the cons is 10% PAR less when you push it to maximum.

I'm not very worried about energy efficiency right now since the electricity bill is included in the rent I pay, the value is the same no matter my consumption. So having this said my priority is to light my plants properly with minimum up front costs.

I find COBs exciting but it isn't the moment for me, at this stage I will simplify. I have many things to worry about in this project, can't spend a lot of time and money on a single thing.
I guess I made my mind and go with a few strips of SMD 5050 instead, this thin strip of LEDs will fit better in the space between shelves, easier to install, no heat sink, no fans, less wiring.
SMD chips come with specific color ranges (eg. 640nm-660nm) or white color (2700k-5000k), I would like to read some thoughts on this before I make a decision. Which ones for growing?

I found this cool thread: https://www.rollitup.org/t/chronikoolz-stripped-lite-peep-show.567470/
With two of those strip that guy grew a cannabis plant, so I'm sure my herbs will be happy as well

Thanks for your time

Metacanna said:

churchhaze,
Thanks for making it clear about the nm / kelvins. Still I wonder, why manufacturers of expensive LED lightning systems are not using white LEDs. Plants are particular sensitivity to particular wavelengths in order to absorb chlorophyll, so wouldn't it be more efficient to run a 640-660nm LED rather than a 3000k LED? The plants would get more useful light with the first, while the 3000K emits useless green light, so less efficient.
Any thoughts about this?

Ok, so lower CRI is better. This one was easy
Just curious, why is 3000K preferred over 2700K?

Yes I saw the spreadsheet of some chips and noticed that the efficiency drops as you put more current on them. Taking Vero 10 for instance, it gives infinite possibilities of configuration, the cons is 10% PAR less when you push it to maximum.

I'm not very worried about energy efficiency right now since the electricity bill is included in the rent I pay, the value is the same no matter my consumption. So having this said my priority is to light my plants properly with minimum up front costs.

I find COBs exciting but it isn't the moment for me, at this stage I will simplify. I have many things to worry about in this project, can't spend a lot of time and money on a single thing.
I guess I made my mind and go with a few strips of SMD 5050 instead, this thin strip of LEDs will fit better in the space between shelves, easier to install, no heat sink, no fans, less wiring.
SMD chips come with specific color ranges (eg. 640nm-660nm) or white color (2700k-5000k), I would like to read some thoughts on this before I make a decision. Which ones for growing?

I found this cool thread: https://www.rollitup.org/t/chronikoolz-stripped-lite-peep-show.567470/
With two of those strip that guy grew a cannabis plant, so I'm sure my herbs will be happy as well

Thanks for your time

Click to expand...

For your first question, the sun is the best source of lighting for plants as we know of. It isn't red or blue or purple, it's a mixture and this mixture is nature's secret sauce to life. This is why a bunch of us here on RIU prefer COBs over single-spectra LEDs.

Now there is a fella by the name of @Positivity who incorporates single spectra LEDs alongside his COBs, therefore evening out his spectra range. I believe others do this too but he does it to the best IMO.

As far as looking at Chronikols PC grow, it looks like a joke. Again, IMO, if your going to grow marijuana, you mine as well do it right without cutting too many corners. It took him over 60x days just to vege that little sprout and the buds didn't even look that impressive. I don't know if it was an auto or something but if I'm going to babysit a plant for 90+ days, I'd better be getting a lucrative return. Some may pipe up saying 'it's about the experience and blah' but growing marijuana in a fuckin' PC case is a little fucked up but then again our species is a little of that too.

Anyways - my point is don't use the LED strips, they suck - at least for the money, effort, and time that your going to put into your project. I agree that COBs aren't for everyone when it comes to cost and/or assembling but maybe there are other ways of achieving your goal of growing microgreens and erbs.

Your first paragraph really confuses me because there's a lot of folks in different forums writing the opposite. They advise to avoid white light and go for blue and red instead. I will have a look on the guy you suggested to see what he has to say about this.

I found the results of Chronikool good enough having in mind the conditions in which he was growing. Really, have a better look on it, don't discard it so easily just because it looks like cheap Christmas lights.
Each strip consumes around 25w, he has 2, so 50w in total. Also consider the very low heat radiated. I don't think 50w of fluorescent lights will produce more bud than this guy with LEDs, so if I think about alternatives to these strips I really don't know.

It's true I will put money, effort and time into my project, definitely I want it to work, but I don't see a logical reason to don't use these lights, what I really needed was a side by side comparison with a T5 or CFL

Metacanna said:

Your first paragraph really confuses me because there's a lot of folks in different forums writing the opposite. They advise to avoid white light and go for blue and red instead. I will have a look on the guy you suggested to see what he has to say about this.

I found the results of Chronikool good enough having in mind the conditions in which he was growing. Really, have a better look on it, don't discard it so easily just because it looks like cheap Christmas lights.
Each strip consumes around 25w, he has 2, so 50w in total. Also consider the very low heat radiated. I don't think 50w of fluorescent lights will produce more bud than this guy with LEDs, so if I think about alternatives to these strips I really don't know.

It's true I will put money, effort and time into my project, definitely I want it to work, but I don't see a logical reason to don't use these lights, what I really needed was a side by side comparison with a T5 or CFL

Click to expand...

I'm no expert on horticulture and far from it. I'm just now, for the first time, growing tomatoes and peppers indoors, and I don't have any prior knowledge to growing microgreens and erbs. From what I've seen on various graphs and charts, every plant has different lighting needs so tomatoes may like 3500K or red-dominant light, while carrots prefer cooler or bluer lighting. While I'm led to believe blue and red LEDs have the potential to grow various forms of vegetation, I have my doubts on whether it's more effective for the plant's vigor and potential.

Again, the sun provides a range of spectra, from UVB to infrared, that boasts the best growth to my knowledge. So unless people are actually generating better yields growing indoors in comparison to outdoors, using just red and/or blue LEDs, I'd seriously reevaluate these other posts you've come across.

With my knowledge of cannabis in mind, Chronikols PC grow is embarrassing when compared to his other, more recent tent grows. To be fair and not so brash, he was after the knowledge of what his project could accomplish and he ultimately harvested the little twig of a plant, so he succeeded in his mission (thumbs up, Chron).

While you may be correct about the strips being cooler than most other lighting applications, such as T5, there's no doubt in mind that the penetration they offer is low, which isn't a huge concern for you because you plan to hang/position the lights slightly above your canopies. Furthermore, the efficiency of those strips can't be all that great (I'm guessing ~25%).

Guessing isn't always the best answer to life's questions, so please educate me if I'm out of line .

I've been investigating this as well. Almost identical situation. I'm currently testing a 5000k 9w cree led bulb from home depot against a 23w cfl and a 6-9 w vero 10 4000k. The results thus far are promising from both the cree and the cob. The cree outperformed all, but also ran as almost as warm as the cfl. The cob performed the worst, however I have a lens on the cob, which was a design oversight. Since most of the light gets reflected back through the heatsink I also think the drivers output is a tad low. However, the heatsink was just above room temp, it was the coolest light ive tested so far. So im going to redesign and redo the experiment and test the output of the driver.

So much to do so Little time

bicit said:

I've been investigating this as well. Almost identical situation. I'm currently testing a 5000k 9w cree led bulb from home depot against a 23w cfl and a 6-9 w vero 10 4000k. The results thus far are promising from both the cree and the cob. The cree outperformed all, but also ran as almost as warm as the cfl. The cob performed the worst, however I have a lens on the cob, which was a design oversight. Since most of the light gets reflected back through the heatsink I also think the drivers output is a tad low. However, the heatsink was just above room temp, it was the coolest light ive tested so far. So im going to redesign and redo the experiment and test the output of the driver.

So much to do so Little time

Click to expand...

What are you basing results on, performance?

Are you using marijuana or tomatoes or?

I'm just curious Bicit, no need to rally troops or raise any gates .

Oh I guess I didn't specify, lettuce micro greens, just comparing relative size and color vs time. Nothing to scientific yet

This is a bit more complicated than it seems. 660nm is absorbed the best by chloraphyll, but that also means it penetrates the least. Yellow-amber, however, is absorbed less and thus penetrates more, and 3000k 80cri peaks around amber. 660nm is basically food for top level canopy while yellow/amber is lower quality food, but reaches lower leaves and causes them to stretch until they see red. Phytochromes determine how much each branch should stretch depending on how much is in Pfr state, so lower branches will have lower Pfr and stretch until they have higher Pfr.

If you have very short leafy greens, it would be possible to get away with just red and blue leds.

All I can say is that it's more complicated than just hitting chlorophyll at the peaks.

Why is 3000k prefered over 2700k? I guess trial and error from the community. Results growing weed with 3000k has showed the best results. I'm sure 2700k white leds would also do great, although with slightly less blue.

Metacanna said:

churchhaze,
Thanks for making it clear about the nm / kelvins. Still I wonder, why manufacturers of expensive LED lightning systems are not using white LEDs. Plants are particular sensitivity to particular wavelengths in order to absorb chlorophyll, so wouldn't it be more efficient to run a 640-660nm LED rather than a 3000k LED? The plants would get more useful light with the first, while the 3000K emits useless green light, so less efficient.
Any thoughts about this?

Ok, so lower CRI is better. This one was easy
Just curious, why is 3000K preferred over 2700K?

Yes I saw the spreadsheet of some chips and noticed that the efficiency drops as you put more current on them. Taking Vero 10 for instance, it gives infinite possibilities of configuration, the cons is 10% PAR less when you push it to maximum.

I'm not very worried about energy efficiency right now since the electricity bill is included in the rent I pay, the value is the same no matter my consumption. So having this said my priority is to light my plants properly with minimum up front costs.

I find COBs exciting but it isn't the moment for me, at this stage I will simplify. I have many things to worry about in this project, can't spend a lot of time and money on a single thing.
I guess I made my mind and go with a few strips of SMD 5050 instead, this thin strip of LEDs will fit better in the space between shelves, easier to install, no heat sink, no fans, less wiring.
SMD chips come with specific color ranges (eg. 640nm-660nm) or white color (2700k-5000k), I would like to read some thoughts on this before I make a decision. Which ones for growing?

I found this cool thread: https://www.rollitup.org/t/chronikoolz-stripped-lite-peep-show.567470/
With two of those strip that guy grew a cannabis plant, so I'm sure my herbs will be happy as well

Thanks for your time

Click to expand...

Well with microgreens it may be the way to go. Most microgreen crops are only grown until they have 1 set of true leaves. The problem with cobs is they're too concentrated for low light requirement crops. A vero 10 mounted at 4inches will make a 12inch circle, however the bulk of the light intensity will be centered in a 4inch circle. Getting even light distribution with a cob starts to become an expensive endeavor. So I've also been looking into SMD LED tapes as an option for growing microgreens. It just seems like a bit of a guessing game to find quality ones.

AquariusPanta, I don't know the exact lightning needed for every herb and microgreen I want to grow, there isn't much information around about it. I'm ready for the trial and error method, fortunately majority of these plants are ready in less than 15 days from seed to harvest, so the learning curve will be fast I believe.

Concerning your second paragraph, no way I would ever say such thing. Instead, I would say it doesn't worth explore "less important" light spectrum for money reasons only. I put it like this, if I can survive with reasonable good health on water, bread and vegetables why would I spend money on more expensive foods? I need to test how expensive "beef" and "salmon" (or 500nm-600nm) are going to affect my plants, but from the evidences I have seen so far I'm very keen to say I won't be surprised.

"Guessing isn't always the best answer to life's questions, so please educate me if I'm out of line."
I'm on the same boat, no moral to say you wrong I'm right, just trying to promote a nice discussion and use your thoughts to make me think

churchhaze, you made it black and white. Thanks a lot.
Following your logic it really won't be necessary to penetrate the canopy on 3 inch microgreens, thus, I think would be wise to save in the ~500nm~600nm spectrum and invest on red and blue.

bicit, that's precisely my problem with COBs, since microgreens cover a large area I believe I would be better with multiple focus of light instead of a single one.
There are some "non-chinese" brands selling SMD LED strips, I would guess they offer better quality.

Metacanna said:

AquariusPanta, I don't know the exact lightning needed for every herb and microgreen I want to grow, there isn't much information around about it. I'm ready for the trial and error method, fortunately majority of these plants are ready in less than 15 days from seed to harvest, so the learning curve will be fast I believe.

Concerning your second paragraph, no way I would ever say such thing. Instead, I would say it doesn't worth explore "less important" light spectrum for money reasons only. I put it like this, if I can survive with reasonable good health on water, bread and vegetables why would I spend money on more expensive foods? I need to test how expensive "beef" and "salmon" (or 500nm-600nm) are going to affect my plants, but from the evidences I have seen so far I'm very keen to say I won't be surprised.

"Guessing isn't always the best answer to life's questions, so please educate me if I'm out of line."
I'm on the same boat, no moral to say you wrong I'm right, just trying to promote a nice discussion and use your thoughts to make me think

churchhaze, you made it black and white. Thanks a lot.
Following your logic it really won't be necessary to penetrate the canopy on 3 inch microgreens, thus, I think would be wise to save in the ~500nm~600nm spectrum and invest on red and blue.

bicit, that's precisely my problem with COBs, since microgreens cover a large area I believe I would be better with multiple focus of light instead of a single one.
There are some "non-chinese" brands selling SMD LED strips, I would guess they offer better quality.

Click to expand...

Here are some numbers and examples I crunched together:

Vero 10, driven at 350mA, producing ~10W

This COB is mounted four inches above soil, giving the circle of light it provides a diameter of sixteen inches, with an area of ~1.4 square feet. This provides 6.8 watts per square foot.

I'm not sure this is the best approach to your scenario but it may help with processing the others.

6.8 watts per square foot isn't a whole lot but it may pass for your veggies.