Higher temps and THC

BobCajun

BobCajun

Well-Known Member
testiclees said:
Nah on the wattage claim. Top quality led IS FAR MORE EFFICIENT THAN HID WATT FOR WATT.

Also not overly expensive if you build your own. RIU led diy is the leader in the cannabis world for latest LED tech and know how.
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Well, this article seems to indicate roughly equal efficacies in PPFD output per watt input. Most of the LED lamps were considerably less efficient than HPS, others were closer. How that translates into actual plant growth and dry weight were not included. It may well be that LED produces more actual weight per watt, since it has a wider spectrum and more far red and blue in its spectrum. Far red is known to increase photosynthesis significantly in some plants and I think Cannabis is one of them. Lights can have equal PPFD levels but considerably different actual spectrums. HPS has a bunch of PPFD in one tight red range.

I've read that LED does expend 70-80% of its power input on heat production, close to that of most other lights including incandescents and HID, just that it comes from the back of the lights rather than from infrared light being shone into the growing chamber as in the case of HPS. You just need to cool the heatsink on top of the LED fixture rather than the chamber itself. Preferably, you would have the top of the lamps outside the top of the growing chamber. I haven't seen anyone actually doing that but that would be my suggestion. Growing chamber temps could thereby be kept quite low.

I actually just ordered a Spectrum King LED light so I'll report back in a few months on the results. They're actually just generic high bay LED lamps but apparently do work for plant growth. This article discusses white LEDs for plant growth. The high bays Spectrum King sells are neutral whites, 4000k. I know because in one video they held a light meter under them and it showed 4000k and the spectrum graph exactly matched the one from Cree LED company's graph for 2600-3700k LEDs. Apparently the 4000k ones are close enough to 3700k that you can't notice a significant difference. This image shows the graph. The red line is the one that the meter showed under the 90 degree Spectrum King fixture. Here's the video with the meter.
 
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testiclees

testiclees

Well-Known Member
BobCajun said:
Well, this article seems to indicate roughly equal efficacies in PPFD output per watt input. Most of the LED lamps were considerably less efficient than HPS, others were closer. How that translates into actual plant growth and dry weight were not included. It may well be that LED produces more actual weight per watt, since it has a wider spectrum and more far red and blue in its spectrum. Far red is known to increase photosynthesis significantly in some plants and I think Cannabis is one of them. Lights can have equal PPFD levels but considerably different actual spectrums. HPS has a bunch of PPFD in one tight red range.

I've read that LED does expend 70-80% of its power input on heat production, close to that of most other lights including incandescents and HID, just that it comes from the back of the lights rather than from infrared light being shone into the growing chamber as in the case of HPS. You just need to cool the heatsink on top of the LED fixture rather than the chamber itself. Preferably, you would have the top of the lamps outside the top of the growing chamber. I haven't seen anyone actually doing that but that would be my suggestion. Growing chamber temps could thereby be kept quite low.

I actually just ordered a Spectrum King LED light so I'll report back in a few months on the results. They're actually just generic high bay LED lamps but apparently do work for plant growth. This article discusses white LEDs for plant growth. The high bays Spectrum King sells are neutral whites, 4000k. I know because in one video they held a light meter under them and it showed 4000k and the spectrum graph exactly matched the one from Cree LED company's graph for 2600-3700k LEDs. Apparently the 4000k ones are close enough to 3700k that you can't notice a significant difference. This image shows the graph. The red line is the one that the meter showed under the 90 degree Spectrum King fixture. Here's the video with the meter.
Click to expand...

Thanks for all that info. I'll give it a close look after work. LED has the huge advantage of directing it's beam in one direction. Loss from 360 degree bulbs is huge.

Only shitty LED's expend high amounts of their power input on heat production. Folks in diy section are building lamps that expend <40% on heat production. For example cxb3590 run at low current are above 60% efficient. It's expensive to take this approach but it has the added benefit of very low heat and emitters can be very close to the canopy. The physics with light and heat is super tricky because eventually all radiance is heat, i think.

My setup uses bridgelux vero's and cree cxb 3590 with a uvb. It's a first run with this rig so I'm watching closely. These lights are 4000k and 3500k


In some recent posts here at RIU Spectrum King got beat up by the diy led crew.
https://www.rollitup.org/t/think-ive-been-led-astray.881108/
 
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jijiandfarmgang

jijiandfarmgang

Well-Known Member
BobCajun said:
I've read that LED does expend 70-80% of its power input on heat production, close to that of most other lights including incandescents and HID, just that it comes from the back of the lights rather than from infrared light being shone into the growing chamber as in the case of HPS. You just need to cool the heatsink on top of the LED fixture rather than the chamber itself. Preferably, you would have the top of the lamps outside the top of the growing chamber. I haven't seen anyone actually doing that but that would be my suggestion. Growing chamber temps could thereby be kept quite low.
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Not LEDs but Medicropper is doing this with Gavitas. He has a seperate chamber of air space that is fan cooled for top of reflector and ballast. I'm sure it would be easier with homebrew leds, as long as you designed for that purpose. Really cost effective way of getting rid of excess heat.


- Jiji
 
S

shloppyjoe

Well-Known Member
jijiandfarmgang said:
Not LEDs but Medicropper is doing this with Gavitas. He has a seperate chamber of air space that is fan cooled for top of reflector and ballast. I'm sure it would be easier with homebrew leds, as long as you designed for that purpose. Really cost effective way of getting rid of excess heat.


- Jiji
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THIS! This is somewhat the room I want! The cleanliness, the amount of reflective material, the symmetry it's all perfect! What a clean and efficient design! If anyone would like to help me out on what materials I need to replicate some of the key features of that flower room I'm all ears! Obviously planning on doing that on a smaller scale also.
 
Entourageeffect

Entourageeffect

Member
Heat is a catalyst for growth, that is why you see rapid growth as it gets warmer. Cannabis is an annual, which means it flowers once a year. Typically heat signals a change in season's, such as going from winter to spring.

As far as THC is concerned, I can't answer the question if it has a direct effect on higher potency. One thing you can do is experiment with UVA and UVB lighting to increase potency and resin production. I say this cause light intensity is sometimes associated with heat.

Some people speculate that cannabis will increase resin production to protect itself from the UVA and UVB lighting, it acts as a sunscreen from what some people say. Have I done any experiments to confirm this? No, but it does sound plausible. Why? Some of the most potent strains come from mountainous regions where they are not getting as much protection from the ozone layer and are exposed to more intense forms of light, people hypothesize that because of this, cannabis reacts and creates more resin to protect itself.
 
hellmutt bones

hellmutt bones

Well-Known Member
a mongo frog said:
You might be. Ive seen 3-4 grows on hear that looked to compete easily with HPS. Quality of bud was to the T, and yield was also great. About a 3x3 area is what i saw, and i think theirs someone with a lamp that covers 4x4. It would be real interesting to see how the 4x4 lamp does. Totally impressed by what their all doing.
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This guy...:wall:
 
ttystikk

ttystikk

Well-Known Member
jijiandfarmgang said:
Good luck to you. I'd like to see this grow.

I'd bet you wouldn't do that well with leds, but I'd like it if you'd prove me wrong.

The only people that seem to do well are small scrogs. Which if thats what your into than I could see using leds.

- Jiji
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The COB led array will light my Vertical ScrOG panels, 6' tall x 4' wide. I do pretty well with them now under 860W CDM lamps;
20150705_164859.jpg

I believe that using 4800W of CXB3590 3500K will produce better yields than a similar wattage of any HID lighting system currently available.

Testing time is coming up soon.
 
ttystikk

ttystikk

Well-Known Member
testiclees said:
Thanks for all that info. I'll give it a close look after work. LED has the huge advantage of directing it's beam in one direction. Loss from 360 degree bulbs is huge.

Only shitty LED's expend high amounts of their power input on heat production. Folks in diy section are building lamps that expend <40% on heat production. For example cxb3590 run at low current are above 60% efficient. It's expensive to take this approach but it has the added benefit of very low heat and emitters can be very close to the canopy. The physics with light and heat is super tricky because eventually all radiance is heat, i think.

My setup uses bridgelux vero's and cree cxb 3590 with a uvb. It's a first run with this rig so I'm watching closely. These lights are 4000k and 3500k


In some recent posts here at RIU Spectrum King got beat up by the diy led crew.
https://www.rollitup.org/t/think-ive-been-led-astray.881108/
Click to expand...
Please tell me more about your UVB supplementation?
 
testiclees

testiclees

Well-Known Member
I was convinced enough by kitehigh's posts to try uvb. i grabbed a 36" t5 arcadia 54w, 12% uvb tube and mounted a fixture under my light.

I am just finishing first run with it. Nothing definitive to report but i am going to keep using it.
 
legallyflying

legallyflying

Well-Known Member
We have run at allot of temperatures across the board and always use co2. Strong light and high temps will ruin good bud.

First thing first, if you want to do it right then go to harbor freight and get an infrared laser thermometer. That way you can see what the LEAF TEMPERATURE IS. We run around 85 in veg at 1500ppm. Same goes for the first couple weeks of flower. Stretch is limited by essentially zero day/night temp differential in those first couple weeks.

Once buds start to form, we cool it down to 80 max. Once trichomes really start to develop it's down to 75. Co2 at around 1k as higher is just a waste at that temp. The last couple weeks we get it as cold as the 40 tons of AC can make it. Which depending in the season is between 70 and 74.

Your terpines will off gas above 75. There are PLENTY of journal articles about this. We have been doing terpines profiles along with our cannaboid testing and I can tell you that same strains, same lights, same nutes.. there was about 50% less terpines in our July harvest because it was soo hot.

Lastly, we ditched the dehu and just run an AC in the drying room. It's about 69-70 degrees in there and the bud smells soooo much better.

Yeah yeah yeah, blah blah blah you can grow weed in 90+ degree heat. But my thought is that we are taking about maximizing quality.

Lastly, I have found that reducing calcium when running them hot and high co2 helps prevent deficiencies from the roots not being able to keep up. With lower N-Ca ratio the plants can uptake greater amounts of nutes. Our veg and early flower mix is like 1 -.75 N to Ca. This does require you mix your own nutes but again, what serious grower is purchasing jugs of water from the hydro store. It's daunting at first, but I calculated we are going to save 8k this year from mixing our own nutrients. Just for reference, all combined a and b veg and flower we run through about 100 gallons of nutrients a year.

Peace out, happy growing and keep that shit chill!!!
 
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