Growing Under LEDs at Temps Above 80F

Fixer · Nov 27, 2020

Koondense said:
Lights off temps seem too high, also trykeeping lower temps if you're so far in flower. The higher temps are really most beneficial in the first half of flowering.

Cheers

Thanks I was not aware of that. I'm running a four strain perpetual harvest. I'm going to have to strike a balance as I can't segregate the plants in each phase of growth. Any suggestions for a good average temp throughout the flower cycle>

prune said:
I posted a bit about this when I was sampling the 1700e.

Infrared light drives the plant. It heats the leaves directly, driving transpiration and growth, while leaving the surrounding air a relatively cooler and cooling temperature.

Heating the air, to drive transpiration, slogs the plant down without an efficient way to regulate transpiration in a positive manner.

IR is such an efficient driver of transpiration and lush growth that I dropped the led's and pay the DE tax, so as to grow the best bud I can...

How about adding 730nm LED light strip? Or do you need more of the IR spectrum?

Fixer · Nov 29, 2020

The buds closest to the lights are showing the foxtailing.

Dion · Nov 29, 2020

Fixer said:
Thanks I was not aware of that. I'm running a four strain perpetual harvest. I'm going to have to strike a balance as I can't segregate the plants in each phase of growth. Any suggestions for a good average temp throughout the flower cycle>

How about adding 730nm LED light strip? Or do you need more of the IR spectrum?

29c

exploziv · Nov 29, 2020

29 C seems way too much. I'd go for 23 to 26 C.

Dion · Nov 29, 2020

exploziv said:
29 C seems way too much. I'd go for 23 to 26 C.

No 29c is the correct ambient temperature for growing under led.

You have obviously never grown under led, if U had U would know that at those temps photosynthesis slows to almost nothing

Keep in mind we need to compare apples to apples

So we are talking about environmental temperature under led

Leaf surface temperature is about the same as ambient under led

Under traditional lights leaf surface temp can be anything up to 7c higher than ambient.

IR has already been mentioned many times

SuperBadGrower · Nov 29, 2020

Yep 29°C... my shit reaches 35°C/95°F every summer and the plants are OK. if you think such temperatures causes problems with LEDs, it's probably a misdiagnosis, something else went wrong or its genetics

below 24 or 25 C (in my estimation) is where you get "plants dont transpire well under leds!!"
And below 22 C you get "led causes deficiencies!!"
the 2 most common 'led problems' ...

f-e · Nov 29, 2020

Fixer said:
View Image
The buds closest to the lights are showing the foxtailing.

Interesting to see this with LED's. Under HID this growth pattern is generally accompanied by some heat stress markers. One being a dark green leathery effect to the curling leaves that's not showing here.

How close to what light?

It's showing signs of re-veg. It won't finish and has become little more than a problem. I would hack it out. There is nothing there to loose. It's just a dark cloud in front of your light.

Just talking out loud, I think it's DLI needs are saturated, and the IR level on this bit is far above the rest of the plants. Perhaps the IR has continued to rise after other colours were saturated. A tip towards the IR spectrum, bringing about the shade response, which is in turn vegetative growth. Almost unfounded thoughts at this point though.

It's just in the way. Hack it out or snap it down. It can't stay there.

Scrappy-doo · Nov 29, 2020

Wow this is news to me. I run my led's at mid 70's F temps and have found some strains to be light sensitive. I wonder if the real culprit could be that my temps are too low and the leaves aren't able to transpire properly for the intensity. So my temps should be mid 80's?

Fixer · Nov 29, 2020

f-e said:
Interesting to see this with LED's. Under HID this growth pattern is generally accompanied by some heat stress markers. One being a dark green leathery effect to the curling leaves that's not showing here.

How close to what light?

It's showing signs of re-veg. It won't finish and has become little more than a problem. I would hack it out. There is nothing there to loose. It's just a dark cloud in front of your light.

Just talking out loud, I think it's DLI needs are saturated, and the IR level on this bit is far above the rest of the plants. Perhaps the IR has continued to rise after other colours were saturated. A tip towards the IR spectrum, bringing about the shade response, which is in turn vegetative growth. Almost unfounded thoughts at this point though.

It's just in the way. Hack it out or snap it down. It can't stay there.

The light was as close as 8" from the highest buds but now some of the buds that were 20" away are exhibiting the same foxtailing. I started the MK under DE HPS 1000w fixtures and was training the plants up trellis netting at the sides of the flood table to maintain 40" from the HPS bulbs. When I swapped the HPS out for the Sinowell LED panels the buds closest to the new lights showed the problem first. These fixtures are 720W and have a built in dimmer but it's first position is at 80%. I'm trying to compare the Sinowell 720W to the Forever Green Indoors 640W fixture and didn't want to dim a full 20% I'm trying to maintain a perpetual grow so I think I'm going to let the MK run to the end and them replace it. It looks like I have more material for the processor.

Thanks to all for the input! Keep it coming.

Fitzera · Nov 29, 2020

Fixer said:
The light was as close as 8" from the highest buds but now some of the buds that were 20" away are exhibiting the same foxtailing. I started the MK under DE HPS 1000w fixtures and was training the plants up trellis netting at the sides of the flood table to maintain 40" from the HPS bulbs. When I swapped the HPS out for the Sinowell LED panels the buds closest to the new lights showed the problem first. These fixtures are 720W and have a built in dimmer but it's first position is at 80%. I'm trying to compare the Sinowell 720W to the Forever Green Indoors 640W fixture and didn't want to dim a full 20% I'm trying to maintain a perpetual grow so I think I'm going to let the MK run to the end and them replace it. It looks like I have more material for the processor.

Thanks to all for the input! Keep it coming.

I just noticed something very similar in my last run. My blurple was replaced with a qb. At the end of the grow I had 1 plant still going, I placed in dead center of my tent. On one side is a 600w hps and on the other is the new 450w qb. The largest main cola looked to be ready on the hps side but 180° of that same top under the qb was full of new growth.

indagroove · Nov 29, 2020

Fixer said:
The light was as close as 8" from the highest buds but now some of the buds that were 20" away are exhibiting the same foxtailing. I started the MK under DE HPS 1000w fixtures and was training the plants up trellis netting at the sides of the flood table to maintain 40" from the HPS bulbs. When I swapped the HPS out for the Sinowell LED panels the buds closest to the new lights showed the problem first. These fixtures are 720W and have a built in dimmer but it's first position is at 80%. I'm trying to compare the Sinowell 720W to the Forever Green Indoors 640W fixture and didn't want to dim a full 20% I'm trying to maintain a perpetual grow so I think I'm going to let the MK run to the end and them replace it. It looks like I have more material for the processor.

Thanks to all for the input! Keep it coming.

Are you sure there's not some stray lamp staying on or partially lit during lights off? It definitely looks like a reveg issue.

indagroove · Nov 29, 2020

Fitzera said:
I just noticed something very similar in my last run. My blurple was replaced with a qb. At the end of the grow I had 1 plant still going, I placed in dead center of my tent. On one side is a 600w hps and on the other is the new 450w qb. The largest main cola looked to be ready on the hps side but 180° of that same top under the qb was full of new growth.

View Image
View Image

Out of curiosity does your QB have red diodes in addition to white, or it it all white diodes?

SuperBadGrower · Nov 29, 2020

Fitzera said:
I just noticed something very similar in my last run. My blurple was replaced with a qb. At the end of the grow I had 1 plant still going, I placed in dead center of my tent. On one side is a 600w hps and on the other is the new 450w qb. The largest main cola looked to be ready on the hps side but 180° of that same top under the qb was full of new growth.

View Image
View Image

Hahah this gave me goosebumps. That's so amazing dude. A 'side by side' if ever I've seen one. Some of the best evidence of how intense those lights are compared to Sodiums... especially at the edges (of an HPS)

SuperBadGrower · Nov 29, 2020

let me throw another one up.
Doing pheno hunts one always escapes me and end up too tall.

cut off the apical bud and you can stop the vertical growth, making foxtails emerge and bulk like crazy.
It's the same as topping a plant in veg. You can snip off the top of a bud or the entire budlet. They call it "backbuilding".
This plant would've shot up like a rocket , but applying this method it makes a fist sized foxtail bud that is excellent quality and high yield

That cycle I didnt even hook up my color leds (You can see them), no shenanigans, no 730 no 660 no BS.

Once it starts you Can't stop the rock. the only way to bring them to a good finish is to dim the lights significantly. Doing that really fucks the light's penetration, so you can't really do it until the very end when the other plants are finished...

Fixer · Nov 30, 2020

Fitzera said:
I just noticed something very similar in my last run. My blurple was replaced with a qb. At the end of the grow I had 1 plant still going, I placed in dead center of my tent. On one side is a 600w hps and on the other is the new 450w qb. The largest main cola looked to be ready on the hps side but 180° of that same top under the qb was full of new growth.

View Image
View Image

That's fascinating!

indagroove said:
Are you sure there's not some stray lamp staying on or partially lit during lights off? It definitely looks like a reveg issue.

The room is exactly the same as it was the last time I grew MK and it came out well. I grew it under the FGI 640W fixtures. What changed is that I started the MK under the HPSs then swapped the HPSs for LEDs and cranked the heat up about 8F.

SuperBadGrower said:
let me throw another one up.
Doing pheno hunts one always escapes me and end up too tall.

cut off the apical bud and you can stop the vertical growth, making foxtails emerge and bulk like crazy.
It's the same as topping a plant in veg. You can snip off the top of a bud or the entire budlet. They call it "backbuilding".
This plant would've shot up like a rocket , but applying this method it makes a fist sized foxtail bud that is excellent quality and high yield

That cycle I didnt even hook up my color leds (You can see them), no shenanigans, no 730 no 660 no BS.
View attachment 553532
View attachment 553533

Once it starts you Can't stop the rock. the only way to bring them to a good finish is to dim the lights significantly. Doing that really fucks the light's penetration, so you can't really do it until the very end when the other plants are finished...

Is the purpose of Backbuilding just to stop vertical growth?

The lights I have use Osram 3535 chips for red. I think they are 660nm. I had the same problem to a lesser degree when I started with DE 1000w HPS 30" away from the plants with the heat up over 80F. I sorted the problem by lowering the temp and beating the plants down to maintain 40" from the HPS lights. If everyone else has success under LEDs at 80F+ I guessing the 720W LEDs are too intense to place as close as I did initially.

SuperBadGrower · Nov 30, 2020

Yeah, backbuilding helps with that. it just stops the apical dominance and causes the side shoots to grow bigger like topping. If you think about it, the structure of the plant is reflected in the (stem) structure of the buds, like a fractal or recursive pattern.
this one is out of control! It's starting a second life. I think even if you cut stuff off, new ones will emerge. Call it a hydra & ride the lightning. :lurk:

Fixer · Nov 30, 2020

They are supposed to be done at the end of this week. I'm going to watch them until then. I have three Snowball waiting to take their place. The plants in the other side of the same table are Mother's Milk. They don't seem to be effected. Time will tell. :good:

Fitzera · Dec 1, 2020

indagroove said:
Out of curiosity does your QB have red diodes in addition to white, or it it all white diodes?

Yes, it has 3500k, 5000k, 660nm and 760nm

Fixer · Dec 1, 2020

So I clipped some of the foxtails off of one of the buds to see what happens.

f-e · Dec 1, 2020

It looks like it's spudding out due to excess heat or light. It's not a nice string of calaxes sticking out that resemble a foxtail

Growing Under LEDs at Temps Above 80F

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