3500k vs 4000k vs 5000k ?

SaltyNuts

SaltyNuts

Well-Known Member
nevergoodenuf said:
I am only a couple weeks in testing CRI, but it is also between 4000k 80cri and 3200k 95+cri. Still the only difference I see is the amount of stretch and the sun leaves are larger under the 95+. So far those are the only differences I can see. Do you guys see anything different?View attachment 3694510 View attachment 3694514 View attachment 3694520
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I see a difference. On the right under the warmer looking light it's a little taller, maybe heading for a bit more lanky growth, not always a bad thing. On the left under the cooler looking light the plants look a bit shorter and more bushy. My initial reaction is that it reminds me of the difference between MH and HPS, although not quite as drastic. It might even be that the color of the lighting tricks me into seeing it that way because that is how I have come to see things.
 
SaltyNuts

SaltyNuts

Well-Known Member
Scotch089 said:
Thanks dude but keep looking around, I'm not trying to come in here and say it's the absolute best most ideal perfect spectra. Look at everyone's results under different combos and decide what you think will work best for you or what you think the plants want. It's not black and white.

I urge everyone else to throw up pics under different Kelvin and come together instead of standing on other sides of the field scrutinizing. (Just don't say monos are useless ;) )
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what he said
 
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churchhaze

Well-Known Member
One of the problems trying to chase the peak of chlorophyll A is that a higher R:FR ratio might actually be counter-intuitive for flowering and desirable morphology. The "inefficient" wavelengths like green and yellow do more than just feed the bottom of the plant. Pfr and Pr is affected by more than just red and far-red. Every wavelength has ratio of absorbance of Pfr and Pr. This ratio determines how high %Pfr will be.



This forms a gradient of %Pfr response, not just R vs FR.

In short, it's more complicated than the chlorophyll A curve. One of the reasons HPS is so great is because of it's huge amount of yellow which lowers %Pfr, particularly on lower branches. HPS's spectrum isn't good in spite of yellow, it's good because of it's yellow. (how anyone can conclude that the HPS spectrum must be poor when it does so well is beyond me)
 
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PurpleBuz

Well-Known Member
churchhaze said:
One of the reasons HPS is so great is because of it's huge amount of yellow which lowers %Pfr, particularly on lower branches. HPS's spectrum isn't good in spite of yellow, it's good because of it's yellow. (how anyone can conclude that the HPS spectrum must be poor when it does so well is beyond me)
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Absolutely, the yellow also plays a big role in light penetration through the canopy.

Did anybody notice that a 3000K/3500K warm white phosphor led spectrum is also loaded with yellow and orange ?
 
tstick

tstick

Well-Known Member
And the know-it-alls know who they are, too....because...they're know-it-alls, after all....see what I'm saying?....*cough*

:)
 
tstick

tstick

Well-Known Member
I'd be interested to know if anyone has grown under yellow, fluorescent bug tubes in combination with black light and strobe light....Yes? No?
 
tstick

tstick

Well-Known Member
churchhaze said:
I'd rather see low pressure sodium mixed with blue and red leds. I've always wanted to see someone try that, but have never wanted to spend my own money just to see what the results would be.
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I hear you, man. I've always wondered just what would happen under some 'extreme' spectrum -just for the sake of seeing what would happen...but, yeah...same here...I just can't bring myself to do it. :)
 
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PurpleBuz

Well-Known Member
tstick said:
I'd be interested to know if anyone has grown under yellow, fluorescent bug tubes in combination with black light and strobe light....Yes? No?
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there was somebody not too long that tried to use an incandescent black light for eod flowering.
but no pics, no data, or even a description of the results.
 
tstick

tstick

Well-Known Member
RM3 said:
The strobe light rules 8)
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I used to have one when I was a kid...I thought it was the coolest thing ever....good thing I didn't have epilepsy...But it would be an interesting experiment to grow some plants under a strobe light...not sure I could predict what would happen, but I bet it would be weird!
 
tstick

tstick

Well-Known Member
Jeez! I just Googled "Growing plants under a strobe light" and there are all kinds of discussions about it! all kinds of opinions, too...Interdasting, eh? :) I haven't looked at any of the discussions yet...just glanced...but I might take a look at a few and see what's up? LOL It should be funny!

I suppose it would depend on the rate of the strobe. If you have it turned up to full-speed, then it's like the light is mostly on...and with the strobe rate turned down, I'm not sure if the plant would even "wake up" and have time to respond before it went back to resting....hmmm...
 
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voon

Well-Known Member
Finally, I would like to ask for your opinion and assessment on the use of high CRi .. I'm out of it somehow confused .. how ever not to reach consensus on it ..
.. However in the table PPF still have a very interesting offer higher CRi90 therefore mainly 4000K for growth .. I think 3500k 90CRi might not be a bad choice at all in combination with 3500k 80CRi .. peak at 630 nm and a high proportion of 600-680nm including FR
very thanks
 

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1234324

Active Member
I chose to go with 2 3590's 3000k @90CRI in series. also I have a bunch of 1watt 6k's all dimmable so I can tune it. + a flouro or 2 for
the rest, uv etc, now I just add blue and or red singles to boost power,
by analising other graphs i decided that 6k peaks in the right nm range for blue and the 3k 90cri peaks in the right red nm ranges also accross the board helping to boost emerson effect and watnot.
So after some quick study and a ruler on my screen I made the logical choice.
not sure if I'm right tho. Notice the colour of the graph lines from cree, the 4k is green!
I wonder how the light spectrum affects the roots?
 

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kristoffolese

kristoffolese

Well-Known Member
mauricem00 said:
every garden center in my area use T8s or T5s. none of the garden centers or hydroponic shops even carry led grow lights.the seeds I use come from seed banks that grow plants under HID light and after many generations of growing under these lights it seems very possible that these plant have adapted to that spectrum. plant have up to 400 different photo sensitive chemicals and use light for many things other than starch production.I do not understand this claim "to much blue light". 6500k T5s produce a lot of blue light as do flora suns but 6500k bulbs work great for vegging plants. adding flora suns to the mix for flowering seems to work quite well even with the large amount of blue light in the spectrum.obtaining broad spectrum blue light with leds is expensive and inefficient.but without it many plant systems can not function. this could make plants more vulnerable to disease and insects. I wonder if this claim that plant need a lot of red light and very little blue light is based more on LED limitations than actual growing experience.
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LEDs have no such limitation. Lights can be ordered in basically whatever color K you want. I used hps/MH since I was 17... been on the full spectrum LED bandwagon for a couple years... never looked back. Higher initial light cost, but I use ~40% of the electricity I used to, for the same output/coverage. My yields are higher, grams/watt is way up, they're a bit frostier now - plus I LOVE the near full dimmability that you get with a good COB or quantum board LED (Loving HLG's qb288!). You can choose what K you want ( I use 3000k for flowering, & for tent veg - does great job controlling height & bushing them way out), and I love the modular nature of leds... you can arrange them however you want, to give very specifically shaped footprints. Very useful for some. In closing - I'm in love with full spectrum leds :) The reduced heat output is awesome, saves cooling money & allows for some amazing tent grows. They last dang near forever - no replacing lights every 6-12 months, have way lower operating costs, allow way better dimmablility control,allow for modular, customized light footprint creation, produce noticeably slimmer stalks/stems without a decrease in yield. Mine are always hollow, yet strong and bendy, easy to ScrOG & never snap from bud weight... though they WILL bend down, down, down lol No problem with the ScrOG net. If you haven't tried out a good led light yet (not the blurple, limited band, cheapies from China), I highly recommend that you do. Check out horticultural lighting group.com - they're always sold out (a testament to how badass they are), but show their re-stock date, as well as offering an email notification option. Or check out rapid led if you're wanting a COB light. Both are great options. I've never looked back :)
 
Trippyness

Trippyness

Well-Known Member
Hello everyone, its been almost 2 years since I started this thread, lots of great info in here and some big names in the community. I appreciate all the comments from everyone and all the data.
I have come back to this thread to run a test. It will take quite a while, but here is the test that will be run.
1,000W DE HPS
5 x 5 Space
9 Plants 3 Gal Coir 3 Different strains staggered in each row for optimal results

Control Run
2100k DE HPS Veg and Fllower

4000k Run Veg + Flower

6000k Run veg + Flower

10,000k Run Veg + Flower

After those runs data will be analysed as well as all samples sent to a lab for quantitative testing.
After this, we will know which Kelvin spectrum is best for what and things can be tweaked based on teh results as well as lighting tech others plan to use.
Then we can run this

Mix Run
Veg: Whichever Spectrum Performs best
Flower Whichever Spectrum Performs Best
Finisher 10k or whichever spectrum performs best

We will then know which Kelvin is most ideal, regardless if its 1 Kelvin or its multiple in different stages.
We will find out and I will post all the information I have in both photos and videos.

This is for my own curiosity and seems has sparked quite a stir.

Please lookout for a new thread starting in the coming weeks.

Regards, Trippy :peace:
 
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