New LED lights stretching

C

cage

Well-Known Member
Hey guys, as the title says I'm having too much stretching with my new LED's.
Below is their spectrum.
spectrum.jpg

I'm thinking the stretch is because of the far-red spectrum.
So how would you suggest I could control the stretch best?

I have 1x mostly blue LED, could it help with swapping the blue one to one of these? For atleast the few first weeks of flowering?
Other option could be just using the blue led for start of the flower 1-2weeks?
Or I could even pull out my HPS and start flower with it, and add these LEDs after the stretch period.

Any thoughts and ideas are welcome!
 
PSUAGRO.

PSUAGRO.

Well-Known Member
Stretching in flower is normal, training (lst, supercrop, net,etc) will help...... Take off those secondary lenses imo, will increase ppf/w , coverage and reduce"hot spots".
 
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OSBuds

OSBuds

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Latest UVA vs UVB cannabinoid test results

LOL @SenseiPrawn I missed have missed the lesson about heat and your scaly mates LEDs. Its been pretty hot on this side of the equator too, so yeah ok I have dropped the EC to 2.3, 2 weeks since flip - 5 to go, my next upgrade will be some Mars UFOs FC Hey Frank, don't listen to Prawn –...
www.rollitup.org
 
C

cage

Well-Known Member
stretch.jpg
PSUAGRO. said:
Stretching in flower is normal, training (lst, supercrop, net,etc) will help...... Take off those secondary lenses imo, will increase ppf/w , coverage and reduce"hot spots".
Click to expand...
Yes, some stretch is and some isn't.
This is definatly spectrum issue since these are clones I've grown under 600W HPS and they didn't stretch half that much.
*edit @ 8weeks flower out of 9-10
 
C

cage

Well-Known Member
Wastei said:
The stretch is from excess nitrogen, not the light source. I see nitrogen toxicity with clawing all over the place.
Click to expand...
I agree that excess nitrogen can induce some stretching and airy buds which could look like something like this.
Clawing could also be from nitrogen or general overfert.

I'm not quite convinced that this is from nitrogen only atleast.
The leaves aren't that dark green nor shiny and I haven't fed them really heavy on nitrogen.

And the fact that the same clone is behaving very differently under HPS.
 
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C

cage

Well-Known Member
Found a photo of them at 3½weeks of flower. At this point I had much excitement :)
I was already then suspecting the spectrum thing but kinda hoped they would fill up.
Now I just want to figure out way to limit that stretch during 1-3weeks of flower.

001.jpeg
 
C

cage

Well-Known Member
Well, since there is not much discussion on the spectrum part, I'll leave this with few pointers I found out.

If there is too high far-red ratio to red spectrum, it will increase stretching as the plants think they are in shade.
Blue spectrum keeps the plant compact.

Higher night temps than day temps limits stretch almost as much as the spectrum part.
 
Kassiopeija

Kassiopeija

Well-Known Member
Wastei said:
The stretch is from excess nitrogen, not the light source. I see nitrogen toxicity with clawing all over the place.
Click to expand...
maybe "abundancy" but "toxicity" is going to drastically reduce the overall growth of said plant, like down to ~~30%, incl. internodes

cage said:
Well, since there is not much discussion on the spectrum part, I'll leave this with few pointers I found out.

If there is too high far-red ratio to red spectrum, it will increase stretching as the plants think they are in shade.
Blue spectrum keeps the plant compact
Click to expand...
your light has very little far red - which is spectrum from ~700 to 780nm. actually red light antagonizes that greatly and ur lamps light does that. the area under the curve of red:far red light of these diodes must be 10:1.

Absorption-spectra-of-phytochromes-and-their-dual-physiological-functions-A-Absorption.png

but one thing comes to mind, if you place too many seeds in a given space the plants mutually shade themselves and then begin a competetive rush for the light once flower sets in.
 
C

cage

Well-Known Member
Kassiopeija said:
maybe "abundancy" but "toxicity" is going to drastically reduce the overall growth of said plant, like down to ~~30%, incl. internodes


your light has very little far red - which is spectrum from ~700 to 780nm. actually red light antagonizes that greatly and ur lamps light does that. the area under the curve of red:far red light of these diodes must be 10:1.

View attachment 5088362

but one thing comes to mind, if you place too many seeds in a given space the plants mutually shade themselves and then begin a competetive rush for the light once flower sets in.
Click to expand...
Hmm, thank you for your input!

I see what you are saying about the far-red-red ratio. And I can't say I have good grasp on how much the ratio should be for plant like cannabis which enjoys high amounts of light.

But I've been running same clones for few runs now. And this LED setup is stretching way more than my 600W HPS setup (like double amount).
The temp differences should be pretty negligible.
So that leaves me thinking it has to be about the light spectrum.
 
Wastei

Wastei

Well-Known Member
Kassiopeija said:
maybe "abundancy" but "toxicity" is going to drastically reduce the overall growth of said plant, like down to ~~30%, incl. internodes


your light has very little far red - which is spectrum from ~700 to 780nm. actually red light antagonizes that greatly and ur lamps light does that. the area under the curve of red:far red light of these diodes must be 10:1.

View attachment 5088362

but one thing comes to mind, if you place too many seeds in a given space the plants mutually shade themselves and then begin a competetive rush for the light once flower sets in.
Click to expand...
Excess N is the right terminology, I stand corrected. It will affect overall growth in every single way. Excess total is was caused it, probably not any problem with the food that's been fed or the light source. Cheers!
 
C

cage

Well-Known Member
Wastei said:
Excess N is the right terminology, I stand corrected. It will affect overall growth in every single way. Excess total is was caused it, probably not any problem with the food that's been fed or the light source. Cheers!
Click to expand...
Yet if you look at the plants at 3½weeks of flower, there isn't a sign of nitrogen excess. But the stretch has already happened..
 
Rocket Soul

Rocket Soul

Well-Known Member
cage said:
Hmm, thank you for your input!

I see what you are saying about the far-red-red ratio. And I can't say I have good grasp on how much the ratio should be for plant like cannabis which enjoys high amounts of light.

But I've been running same clones for few runs now. And this LED setup is stretching way more than my 600W HPS setup (like double amount).
The temp differences should be pretty negligible.
So that leaves me thinking it has to be about the light spectrum.
Click to expand...
Hard to believe its red/farred ratios if youre seeing more stretch than hps as hps has an even stretchier ratio. Can you confirm what the par output is at cannopy with both lights? If the new lights have lower output at cannopy than the hps then that might cause stretch aswell.
 
C

cage

Well-Known Member
Rocket Soul said:
Hard to believe its red/farred ratios if youre seeing more stretch than hps as hps has an even stretchier ratio. Can you confirm what the par output is at cannopy with both lights? If the new lights have lower output at cannopy than the hps then that might cause stretch aswell.
Click to expand...
Mm, I thought the HPS barely has any far-red?
As for the PAR output, I dont have meter. But the 2x LEDs are 125W each.
So I reckon they should have bit more PAR output than the HPS.

Sylvania_Grolux_600w_Spectral_Distribution.jpg
 
C

cage

Well-Known Member
grotbags said:
looks like rocketsoul has nailed it, your 2 x 125watt led are not going to be anywhere close to the same output as a 600watt hps...
Click to expand...
I found numbers for the LEDs, 1345 Umol/300mm.
For HPS Photon flux PAR PPF (100 h): 1000 µmol/s.

Not quite sure if the numbers are comparable.
But I've grown with 250W and 400W HPS before, so I don't think this is from the lack of light.
Also the growth speed during veg and early bloom doesn't really suggest lack of light.
 
grotbags

grotbags

Well-Known Member
cage said:
I found numbers for the LEDs, 1345 Umol/300mm.
For HPS Photon flux PAR PPF (100 h): 1000 µmol/s.

Not quite sure if the numbers are comparable.
But I've grown with 250W and 400W HPS before, so I don't think this is from the lack of light.
Also the growth speed during veg and early bloom doesn't really suggest lack of light.
Click to expand...
i might be getting my wires crossed here, what wattage are the led lights you have?.
 
Shaded420

Shaded420

Well-Known Member

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you would need about 400w of LED to compare to a 600w HID

these lights are trash 720cdn for 125w of output, utterly ridiculous.
 
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