DIY led grow

churchhaze

Well-Known Member
These are great results. I really want to experiment with far-red leds myself. I'm interested to see how your results will differ with 2/3 the far-red removed and replaced with blue.
 

PetFlora

Well-Known Member
Still, nice looking nuggzs.

I have finally figured out that > 30% red accelerates stretch, even during mid-late during flower



Coming along nicely. Quality is solid, that was the main goal, so I'm overall happy. The main tops are really nicely developed, just need more of them. Lots of scraggly lower growth that stretched up never had a chance at filling out.

Next grow a shorter and more even canopy is in order. Hopefully the blue leds I add, and 2/3 far red removed, will make that happen.
 

Positivity

Well-Known Member
These are great results. I really want to experiment with far-red leds myself. I'm interested to see how your results will differ with 2/3 the far-red removed and replaced with blue.


I wouldn't experiment too much with far red after this. At least in an always on situation. Although if my next grows quality sucks then I'll have to consider putting them back in TOGETHER with blues.


I'm going to stand by my ass-ump-tion for now that whites benefit from deep red supplementation. Possibly even 405nm, 430nm, and 470nm where they tend to drop off.
 

churchhaze

Well-Known Member
I've always thought similar. Almost all deep red (660nm) is absorbed by the top layer of growth with very little penetrating. Deep red covers the top of the plant like a blanket of high quality light. It also causes the top layer to have a higher % of phytochromes be PFr than lower branches where the deep-red is filtered out.

The wide spectrum leds (white) provide yellows and greens for the lower layers of growth which aren't fully absorbed by the top layer. Deep red doesn't penetrate, but yellow does. This has sort of a calibrating effect on the plants as a whole.

I think the term "penetration" makes very little sense when thought of traditionally. The wavelengths that have the worst penetration do so because those wavelengths are absorbed the best!

I'm going to stand by my ass-ump-tion for now that whites benefit from deep red supplementation. Possibly even 405nm, 430nm, and 470nm where they tend to drop off.
 

Positivity

Well-Known Member
Pet flora>> didn't even know they had floros with that type of spectrum. Noticed anything with and without? Too much stretch if left on in early flower?




Churchhaze>> could you refresh my memory on Pfr. You said deep red causes higher Pfr on top layer where most absorption takes place. I've always had a hard time grasping that topic. Maybe just touch on benefits of higher Pfr?


while I do read a lot on spectrum I probably take more from seeing results of others grows. Of course things like genetics, feeding regime, and other environmental factors can skew the results.


The white grows I've seen looked great yield wise but something seemed to be missing in the end. The xmls hit 630nm hard enough so the next logical step for me was to boost the 660nm. Maybe even better would be to hit from 630nm to 680nm evenly
 

Positivity

Well-Known Member
Did some reading on far red and Pfr again. Think next run far red is completely out. I'll just take what far red my whites are giving me and widen the gap between red to far red ratio.

so next run is looking like..
22 ww xml l2 3200k
10 nw xml l2 5000k
44 luxeon es deep red bin Ex6
6 luxeon es royal blue.....new
4 luxeon es blue.....new
2 exotic 405nm
2 exotic 430nm.....new

plus supplemented by 25w Arcadia t5 UVB

So if I get too little stretch on the next run, I will take out the nw xmls and replace with a warmer kelvin.

This should be quite a bit different from an all white run. Hitting everything across the board, just some harder than others. Kind of a blend of two theories, white and multi color, with white leading the way.
 

churchhaze

Well-Known Member
Far-red could be useful for causing lower branches to stretch until it sees direct light. What's interesting is that 660nm is absorbed by chlorophyll well, but 730nm penetrates easily, like green. This causes a strong shade avoidance effect.

Also, when the lights turn off, %Pfr (percent of phytochromes as Pfr rather than Pr) slowly lowers to 0% in the dark. Experiments have shown that a short pulse (1-5 minutes) of 730nm light will cause %Pfr to go to 0% immediately sleeping. Shining a pulse of 660nm light right after the 730nm pulse undoes this. (this is seen when you turn the lights on at night and potentially ruin the flowering cycle)

HPS does have quite a bit of 730nm relative to 660nm if you look at it's spectrum, it's maybe 2 red to 1 far-red?

Did some reading on far red and Pfr again. Think next run far red is completely out. I'll just take what far red my whites are giving me and widen the gap between red to far red ratio.
 

anomuumi

Member
Regarding the stretching, I think by looking at the pics before you flipped, you just overvegged a bit. That might have been the biggest contributor to why you have so much stalk. Anyway, nice thread, good pics and looking forward to seeing more!
 

PetFlora

Well-Known Member
Pos.. the problem with experimentation is needing a control, which I cannot afford, nor am I 'that' geeky

I had way too much red (> 600) in mid flower, and have not noticed any tangible benefits from replacing 2 with 2 UVL Red Lifes CWs, was hoping the CWs would turn trics amber, but this is 3rd grow and not so far.
 

Positivity

Well-Known Member
Day 45

gonna have to chop early. Had a ventilation mishap, circ fan got unplugged all week. Plus I shut my main fan down a few hours a day during night cycle to save electric. Bad combo caused some budrot.

But I'm still happy. The quality is so high on this run otherwise. The smells are outrageous...bud development is beautiful. Starting about a 2 week flush then chopping early. Time to get the new leds in and make some adjustments. Next run should be off the hook


image.jpgimage.jpgimage.jpgimage.jpgimage.jpgimage.jpgimage.jpgimage.jpg
 

churchhaze

Well-Known Member
Awesome results despite the bud rot. Have you considered using the 730nm leds for 10-15 minutes after the lights go out? It's supposed to cause the plant to go to sleep immediately instead of over 2 hours, thus making the effective night length about 2 hours longer. A lot of led growers have tried it and noticed a quicker transition period from veg after to flowering after changing lights to 12/12.

This grow uses the 730nm leds (the flower initiator) that way and some others comment on how they use it in their setup too and notice an obvious difference.
https://www.rollitup.org/led-other-lighting/656542-flowering-cree-bulbs.html

He's using this 10W 730nm setup which has a decent explanation of the phytochrome system :

http://growlightsource.com/products/indoor-outdoor-led-grow-lights/the-flower-initiator-10-watt-ip65-indoor-outdoor-grow-light/


"Short Day Plants:

Those that flower as the days length decreases in length, as in the late summer, fall or winter. The flowering process is actually controlled by the length of the night. With proper use of the Flower Initiator your plants will respond as if the night as if it is two hours longer than it actually is, Flowers then develop faster, with the urgency of being in a longer dark period.
Far RED LED Light:

Triggers the Phytochrome Pfr/Pr state to change or switch, Pfr is the Waking or Active State and Pr the Sleeping or Resting State. Far RED light causes a switch from Pfr to Pr in seconds, assuredly within minutes. Your plants go to "Sleep" quickly, in mere seconds to a few minutes, rather than in the normal two hours required by nature, outdoors or indoors. This rapid state switch will provide for more rapid, accelerated, Flower development."
 

Positivity

Well-Known Member
I actually have thought a lot about it. My flowering was quick this time around, at least a week ahead. Think I'm going to make a flower trigger out of my 740s. It will probably be a lot better not having them on all the time inducing the shade avoidance.
 

stardustsailor

Well-Known Member
...
slides pfr.jpg
..

Red wl irradiation should be greater than green wl irradiation ..
( Very crucial when combining white & red leds ...)

Along with : Red wl irradiation should be greater than far-red wl irradiation ..
( very crucial when combining FR leds / High CRI WW leds with red leds ...)
 

churchhaze

Well-Known Member
Great diagram!

I had a chart long ago that showed stretch rate is logarithmically proportional to %Pfr. (high %Pfr, low stretch)

%Pfr = Pfr / (Pfr + Pr)

%Pfr can't get higher than ~85% because Pfr and Pr both absorb at 660nm even though Pr absorbs it way more.

At 730nm, only Pfr absorbs so %Pfr can go as low as 0% (100% Pr).

...
View attachment 2919868
..

Red wl irradiation should be greater than green wl irradiation ..
( Very crucial when combining white & red leds ...)

Along with : Red wl irradiation should be greater than far-red wl irradiation ..
( very crucial when combining FR leds / High CRI WW leds with red leds ...)
 

Positivity

Well-Known Member
Alright I have a better grasp of this far red wl now. Thanks for all those sources most were new to me. It's the first time I've seen it shown to affect germination and seed set. Looks to be a very important point for anyone diying a light, keep the far red levels in check. Unless you want a first hand lesson like me ...lol

funny how it's so prevalent in commercial fixtures. The output from most 730nm leds must be minimal. These ledengin 10 watters are the real deal, should make a good flower trigger.
 

churchhaze

Well-Known Member
I guess I was high when I read this chart. (heck, I probably am now too) I just noticed:

"Response to shade:
Rate of flowering - Markedly increased
Seed set - Severe reduction
Fruit Development - truncated
seed germinability - severely reduced"

My theory with "shaded" plants, %Pfr is already low when the lights go out, so it takes less time in the dark to reach 0% (all phytochrome as Pr).

This would explain why having the 730nm leds on all day seemed to improve flowering speed (maybe), although maybe having a pulse of FR after the lights go out would make that unnecessary.

If you had a pure 660nm light source, the %Pfr should theoretically be around 85% and thus take the longest amount of time in the dark for it to become 0%.


...
View attachment 2919868
..

Red wl irradiation should be greater than green wl irradiation ..
( Very crucial when combining white & red leds ...)

Along with : Red wl irradiation should be greater than far-red wl irradiation ..
( very crucial when combining FR leds / High CRI WW leds with red leds ...)
 

Positivity

Well-Known Member
It does make lots of sense looking at it like that. I had less Pfr due to prevalent far red making flowering faster. It would seem best to max out Pfr with minimal far red and use the far red just at the end for an instant reversal.
 
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