Can IR Lighting Offset Need For Higher Temps With LED Lights

BB Boomer

BB Boomer

Well-Known Member
I am aware of the different temps required for each type of lighting. Can I use supplemental ir light bars to avoid the need for temps in the 85° F range and operate at 78° F like hid lighting?

I want to switch from cmh lighting to all led lights for a open air grow in my basement. Without any lighting on the ambient temp stays steady at 73° F. With my four cmh lights on the temps range between 77° and 79° F. I don't want to use tents and heating the whole basement isn't economically feasible.
 
Thanks.
I am growing in supersoil. The led lights I want to switch to is four Black Dog PhytoMax 8s. My grow area footprint is 3 feet x 12 feet. Currently I am running four SUNSYSTEM 315w cmh lights.
 
In a recent video Bruce says the 85° target works best with LEDs when c02 and all other parameters are pretty maxed out and the less optimal your environment is you shouldn't have to stress as much about holding that high of a temp, they will grow fine under the LEDs at your current temps.

And those blackdog LEDs do run pretty warm, you might even get more heat with that setup over the current cmh's.
 
BongChoi said:
In a recent video Bruce says the 85° target works best with LEDs when c02 and all other parameters are pretty maxed out and the less optimal your environment is you shouldn't have to stress as much about holding that high of a temp, they will grow fine under the LEDs at your current temps.

And those blackdog LEDs do run pretty warm, you might even get more heat with that setup over the current cmh's.
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85° is a good temp for veg and the first couple of weeks of flower but, after that, temps in the 80's will decimate cannabanoids.

One of Bugbee's students, Mitch Westmoreland, studied the impact of ambient temps on cannabis in 2020 but that info didn't seem to get much traction. Westmoreland released a video about a year ago containing some of the research he did for his PhD thesis (under Bugbee). Below is a screenshot from the video.

In a nutshell, Westmoreland advises 85° through (about) the second week in flower because that's the time when the plant is building the infrastructure to support flowering. Once "build out" (stretch) stops, Westmoreland recommend dropping the ambient temperature so that none of the buds have a temp >78°. And that 78° mark is both the highest temp he recommends as well as being strain dependent.


1740524229332.png


 
I left out a lot of detail there but he did mention exactly the same tapering off after stretch. He does all his studies with c02 so he was theorizing(in the WTG episode w/ Bruce) without c02 the max temp of that curve could be slightly lower
 
Fwiw lightning a open area creates a lot of wasted light intensity.

A reflective wall 1ft back.
Screenshot_20211224-193620.png
A reflective wall next to the light.
_20211224_194038.JPG
That's 50% less without something reflecting light back in.
 
Thanks for all the awesome information. I am going to go for it with the switch to led.
I agree allot of light gets wasted with a open grow but I just like to do it that way. I am not worried about getting every gram possible as I just grow to cover my needs. My cmh lights have been good to me for a long time but it's time to move into the 21st century. I did buy a Apache led back when led was just becoming a thing for growing cannabis. The technology has improved so much since then that I feel secure it will be a good investment.
Now what to do with all the hps and cmh fixtures I have built up?:roll:
 
The other lights would be useful for trying a checkerboard style grow and seeing how the broader spectrum changes things. Some people really like using a mix of lights during flower vs. LEDs alone.
 
Delps8 said:
85° is a good temp for veg and the first couple of weeks of flower but, after that, temps in the 80's will decimate cannabanoids.

One of Bugbee's students, Mitch Westmoreland, studied the impact of ambient temps on cannabis in 2020 but that info didn't seem to get much traction. Westmoreland released a video about a year ago containing some of the research he did for his PhD thesis (under Bugbee). Below is a screenshot from the video.

In a nutshell, Westmoreland advises 85° through (about) the second week in flower because that's the time when the plant is building the infrastructure to support flowering. Once "build out" (stretch) stops, Westmoreland recommend dropping the ambient temperature so that none of the buds have a temp >78°. And that 78° mark is both the highest temp he recommends as well as being strain dependent.


View attachment 5454143


Click to expand...
I ran this exactly based on the research
 
Delps8 said:
How different was it from your normal growing practices (temperature, light, RH, etc.) and how did it turn out?
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2nd grow. First grow was hydro and I failed badley. Now all organic in soil.
Week 7 of flower.
IMG_20250228_083526047_HDR.jpg
Since week 5 have been at 75/65. Smells great and very sticky.

Way to much information proving to me that higher temps reduced overall resin retention and the lower temps caused a larger response from the plant to produce end of flower resin without the risk of reveg or herm possibilities that very high lights can bring.
It took about 40 hours to run through the master thesis because of so much of the biological explanations needed explaining at a more basic level than it was written for.

I will let you know but I have already read a few posts from long term growers who changed to led and struggled until they went with this method.
 
Jimski said:
2nd grow. First grow was hydro and I failed badley. Now all organic in soil.
Week 7 of flower.

Since week 5 have been at 75/65. Smells great and very sticky.

Way to much information proving to me that higher temps reduced overall resin retention and the lower temps caused a larger response from the plant to produce end of flower resin without the risk of reveg or herm possibilities that very high lights can bring.
It took about 40 hours to run through the master thesis because of so much of the biological explanations needed explaining at a more basic level than it was written for.

I will let you know but I have already read a few posts from long term growers who changed to led and struggled until they went with this method.
Click to expand...
Nice looking plants. What's that black hose coming in the tent? I'm asking because it looks similar to the hose from the AC Infinity heater.

The research Westmoreland did re. temps in flower back in 2020 in in the video below.


Really interesting what you pick up watching older vids.

At the 9:10 mark in the video—the increase in yield as temperature increases is very, very low and, given that it's pretty much the same value as the error bars, I want to check other sources re. temperature.
1740859011686.png

P was in his video from last year but he reported on it in the 2020 video, as well.
1740858944643.png
 
Delps8 said:
Nice looking plants. What's that black hose coming in the tent? I'm asking because it looks similar to the hose from the AC Infinity heater.

The research Westmoreland did re. temps in flower back in 2020 in in the video below.


Really interesting what you pick up watching older vids.

At the 9:10 mark in the video—the increase in yield as temperature increases is very, very low and, given that it's pretty much the same value as the error bars, I want to check other sources re. temperature.
View attachment 5454777

P was in his video from last year but he reported on it in the 2020 video, as well.
View attachment 5454776
Click to expand...
The back hose is the ACi humidifier. The ACi heater box comes in from the bottom and points up.
Vivosun app controls lights and duct/vent fans and the ACI app runs the heater and humidifier.
The drop down cable has 5 sensors in it and 2 more placed around
Hello my name is Jimski and I am a data addict.
 
BB Boomer said:
Thanks for all the awesome information. I am going to go for it with the switch to led.
I agree allot of light gets wasted with a open grow but I just like to do it that way. I am not worried about getting every gram possible as I just grow to cover my needs. My cmh lights have been good to me for a long time but it's time to move into the 21st century. I did buy a Apache led back when led was just becoming a thing for growing cannabis. The technology has improved so much since then that I feel secure it will be a good investment.
Now what to do with all the hps and cmh fixtures I have built up?:roll:
Click to expand...
Can I ask what the reason for wanting to make the switch is?
And why black dog?
 
Just use more watts of led would be my advice, orrr use a hid between 2 LEDs, or a led between 2 hids, I'd allways go for adding extra par watts vs adding standalone ir. I grew with hps and led for years and I found it better than either alone. The differing fundamental properties of light distribution from each system complement eachother so well
 
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