Best spectrum from LED

I am agree to say that something is missing in my spectrum. I take it by the minimalist way, for me it works, but in the future if some discover that an another wavelenght is useful, I will add it !
I am not blocked on this, but I think this way, I have the most important part of the useful spectrum.
 
While the idea of a simple, very low power lamp like you have is nice, you mentioned something VERY important:
You said each of those lamps is FOR ONE plant.

We know that, the usual blurple lights have very poor spread and possibly also very poor penetration down into the canopy.

Right now I have 8x plants and TONS of seedlings in my greenhouse, under 4x CREE CXB 3590 COBs driven at 1620mA

So, you say your type of LED is "the best" LED, but it also means I would need at a bare minimum eight of your lamps for my plants plus probably 2 more for my seedlings/chillies....all this stuff is currently under 4x COBs.

So if I need 8-10 of your "best lights" to make good for 4x CREE COBs, then the story looks entirely different, also in terms of costs and efficiency. Basically needing to cover the entire ceiling with lights I cannot really see as "the best" solution.

As for spectrum etc....it might be that this limited spectrum is good and you don't need more than 450nm and 660nm and maybe IR. But it also becomes relative if you need 8 or 10 such lamps for a number of plants. Then the "waste" of CREE COBs with their white spectrum might ultimately be less than what you waste by needing 10 or so lights. Do you see what I am saying?

On the other hand, it might well be that for ONE or TWO plants your light is "better", more effective etc....but I don't think that many folks grow only one or two plants.
 
Yes flexy123, light spectrum AND light intensity are both critically important. For cannabis, a general rule of green-thumb is a minimum of 600 PPFD, but 1000 is better.

General note to all: Measuring light intensity with lumens is NOT an effective method of assessing the effectiveness of horticulture lights, because lumens only accounts for light between 500 and 600 nm.

flexy123 said:
While the idea of a simple, very low power lamp like you have is nice, you mentioned something VERY important:
You said each of those lamps is FOR ONE plant.

We know that, the usual blurple lights have very poor spread and possibly also very poor penetration down into the canopy.

Right now I have 8x plants and TONS of seedlings in my greenhouse, under 4x CREE CXB 3590 COBs driven at 1620mA

So, you say your type of LED is "the best" LED, but it also means I would need at a bare minimum eight of your lamps for my plants plus probably 2 more for my seedlings/chillies....all this stuff is currently under 4x COBs.

So if I need 8-10 of your "best lights" to make good for 4x CREE COBs, then the story looks entirely different, also in terms of costs and efficiency. Basically needing to cover the entire ceiling with lights I cannot really see as "the best" solution.

As for spectrum etc....it might be that this limited spectrum is good and you don't need more than 450nm and 660nm and maybe IR. But it also becomes relative if you need 8 or 10 such lamps for a number of plants. Then the "waste" of CREE COBs with their white spectrum might ultimately be less than what you waste by needing 10 or so lights. Do you see what I am saying?

On the other hand, it might well be that for ONE or TWO plants your light is "better", more effective etc....but I don't think that many folks grow only one or two plants.
Click to expand...
 
SuperFunker said:
Yes flexy123, light spectrum AND light intensity are both critically important. For cannabis, a general rule of green-thumb is a minimum of 600 PPFD, but 1000 is better.

General note to all: Measuring light intensity with lumens is NOT an effective method of assessing the effectiveness of horticulture lights, because lumens only accounts for light between 500 and 600 nm.
Click to expand...

i run about 1000ppfd with a combo of bridgelux, cree and t5 uvb. works great but it took me a while to discover that good clearance is critical.
 
The UVB is deployed for all of flowering. I dont have it on a timer. I turn it on for a few hours each day.
I am vegging under a different rig that is completely cfl.
 
groovy... have you ever tried to tighten your use of uvb (ex 2 to 4 hours per day during last 2 to 3 weeks of flowering)? what im wondering: would narrower approach facilitate larger bud development in early flowering (without uvb), then later induce desired thc production at mid to end of flowering (with uvb)?

LilyDanktree said:
The UVB is deployed for all of flowering. I dont have it on a timer. I turn it on for a few hours each day.
I am vegging under a different rig that is completely cfl.
Click to expand...
 
SuperFunker said:
groovy... have you ever tried to tighten your use of uvb (ex 2 to 4 hours per day during last 2 to 3 weeks of flowering)? what im wondering: would narrower approach facilitate larger bud development in early flowering (without uvb), then later induce desired thc production at mid to end of flowering (with uvb)?
Click to expand...
Is there reason to believe that UVB exposure slows bud development? I hadn't considered that.

This is just my second grow with the UVB. Both times the t5 was lit between 2-5 hrs per day, almost every day. I thought that varying amounts of UVB would elicit a decent response. On the second grow I lowered the tube to about 10-12" clearance.
 
re uvb-dosing: read one study that claimed 3 to 5% increase in thc, but a reduction in yield (damages plant) which is why wondering how much uvb is necessary to pump up the thc while trying to max flower size...

note: i dont know how credible the study was and i dont use uvb, im just curious...

LilyDanktree said:
Is there reason to believe that UVB exposure slows bud development? I hadn't considered that.

This is just my second grow with the UVB. Both times the t5 was lit between 2-5 hrs per day, almost every day. I thought that varying amounts of UVB would elicit a decent response. On the second grow I lowered the tube to about 10-12" clearance.
Click to expand...
 
I just want to add something...

There really is no "best" spectrum, it all depends how you want to grow.

Folks did comparison with the CREE CXB COBs and they run them anywhere from 2700K (very warm white) to 4000K (cool white), the differences there are said to very subtle.

For a light with many blues (or more blue in the spectrum), plants usually grow shorter & bushier while with a spectrum of less blues they might stretch out more, but of course still grow.

So...say someone wants to have a vegging lamp and he/she thinks that for vegging more blues would be best, alright, but it can be that the person wants the plants grow TALL too, so you wouldn't automatically want the light with the most blues because you want it to stretch a little as well. So it always depends on your needs.

I guess the "best" spectrum is a balance of reds and blues because you want the plant to grow as fast and lush as possible but not so much it wouldn't stretch up.
 
green light is important.......like many have said red and blues are inadequate in stimulating the healthiest responses. All the stoners with " real practical experience" probably know better but NASA disagrees

NASA Technical Reports Server (NTRS) - Sole-Source Lighting for Controlled-Environment Agriculture

Green light.
Green light (500-600nm) falls between broad-band blue and red light
along the PAR energy spectrum. Green often is disregarded as an unimportant
waveband in photosynthesis because absorption spectra of extracted leaf chlorophyll
pigments indicate very weak absorption in the green region of the PAR. Because
chlorophyll has major absorption peaks only in the red and blue regions, researchers
initially selected first red, later blue, LEDs for first-generation LED arrays to support
plant growth. However, intact leaves do absorb considerable green light, and in a
relative quantum-efficiency curve for photosynthesis vs. PAR wavelengths, some
wavelengths of broad-band green actually are more efficient than certain
wavelengths of the blue band. Overall, however, broadband green is slightly less efficient than broadband blue. However, when leaf canopies close, red and blue light are absorbed strongly by upper or outer leaf layers, whereas green light penetrates to interior leaf layers, where it subsequently is absorbed and drives photosynthesis of the inner canopy (14). Thus, light sources containing some green can be more effective in stimulating crop growth than are red + blue sources alone,much as when
foliar canopies are closed. When applied together with blue light, green has effects
opposite to blue on stomatal aperture (15). Yet another useful feature of green light
is that the human eye perceives red + green + blue (RGB) light as white light, so if all
three wavebands are present simultaneously in plant-growth light, researchers and
growers are able to visually evaluate the stress status of crops, the incidence of
physiological disorders, and “true” leaf color (the way it looks outdoors), whereas if
only red + blue are present, green tissue looks purple, grey, or black, and
physiological stress or disease diagnosis is difficult(...)
 
Yes I have to say I see my COB lights (3500K white) as advantage, it is much better to actually *see* how your plants are doing. And yes, just because plants are using less green doesn't mean they are not using it at all. I always think it's funny how exactly THOSE companies who use blue&green lights call their lights "full spectrum", only white is really "full spectrum".
 
Hey Flexy,

I skimmed through your journal. Wow you learned a lot pretty quickly. How did it turn out with your 3590 bars?

Have you tried out any of the ACE genetics? They are in Spain and have quite an excellent rep. The very first MJ i ever grew was their Nep Jam. It was well enjoyed.
 
Hey!

The 3590 works like a charm, I added a fourth fan since the first LED of the four didn't have one - I was a little afraid about temps, especially in summer. I also moved the driver a little up, above the fan. This makes a HUGE difference in temps since otherwise the fan will just blow hot air from the driver down to the LED.

light-3.JPG


I really wanted to start a new journal with the new lights, but I am shortly before switching to Hydro, respective Hempy buckets with Perlite/Vermiculite.

I am so over soil! I was never 100% satisfied with my initial grows and speed of growth and always run into one or the other problem, like yellowing and bugs. I want to try Hydro and also look into different nutes. I still need the right type of Vermiculite (I just ordered) since the one I got today is not coarse enough and might cause root rot.

As for seeds, believe it or not, I am buying cheap €1 bulk seeds and besides the very first seeds we got when we started I don't buy premium seeds anymore. I found at least two vendors who sell quality "bulk" seeds for €1/pop which until now all have germinated. One good store-brand type of seeds I discovered is "Geaseeds", they have all popular and common varieties, autos and feminized for €1.

Right now the greenhouse is full to the rim, 4 Autos which are flowering (Critical, White Widow, AK I think) as well as 2x Somango and 2x Northern Lights which are vegging. Planning to put them upstairs in the next days to make room in the greenhouse for the hydro stuff.
 
LilyDanktree said:
More on green light

Green Light Drives Leaf Photosynthesis More Efficiently than
Red Light in Strong White Light: Revisiting the Enigmatic
Question of Why Leaves are Green


https://pcp.oxfordjournals.org/content/50/4/684.full.pdf+html
Click to expand...

Could u give me advise on these diodes

CXB1304

CXB1512

would these work for what u are talking about... i might pick some up.

they are not the ones u have but i could get a few more.. i mean i only want a small 150w ... i need enough light for 3 feet x 3 feet tent. than
 
SmbolicPhrase said:
Could u give me advise on these diodes

CXB1304

CXB1512

would these work for what u are talking about... i might pick some up.

they are not the ones u have but i could get a few more.. i mean i only want a small 150w ... i need enough light for 3 feet x 3 feet tent. than
Click to expand...


SP sorry i am not an expert at all on the cree products. You can find more info by googling around for the forum which has a large area devoted to LED. If you search for diy cree cxb you should be able to find experts who can speak to your issue.
 

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