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Light vs Heat tradeoff

I have a question I can't seem to find the answer to. Perhaps you can help me.
I understand that temperature, humidity and light intensity must be as close to perfection as possible.
However I find my self in the situation where I can no longer control heat and humidity using ventilation.  Ventilation is optimal.  I do not want to make the transition to an air conditioned space due to complexity and cost.  
So my question is this? Which is more important? Heat or light intensity? For example to lower the temp 3° Should I use less light wattage.  Or is light intensity more important than the 3 degree drop in temperature.
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Replies (9)
  • 3 degrees isn't going to make a difference.

    What temps/ rh are you running?

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    • I agree with rbtasq...

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      • You should look into VDP, you may find a balance that will work without much change or investment.

        https://www.cannabissciencetech.com/view/understanding-vpd-and-transpiration-rates-cannabis-cultivation-operations

         

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        • that is a good one cpw .....

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        • If you can swing buying a 30qt dehumidifier it will help with your temps a little bit, I know heat is an issue for many so I have heard of people running there lights at night and lights out during the day, useless to you on this grow but food for thought, also fans don't hurt.

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          • Thanks cpw and hulk for your help.

            Cpw, wow I did not know that thanks for the link about vdp. That's great information in my case. Since I deal with high Temps and high humidity it seems to naturally work in my favor. 85 degrees and 70% humidity is something I can achieve in my native environment.  Interesting that as heat rises, a higher humidity is beneficial for prime vdp. Most growers demand 76/55. But 85/70 gets the same results with less energy in my case. Thanks again. 

            What other advanced sites are your favorites?

             

            Hulk, I tried a dehumidifier but they generate a lot of heat. The night switch is a good idea though. I  will try that. I have plenty of breeze so can't tweak that anymore. Thanks for you help and suggestions. 

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            • This is one of the most advanced sites I have found, there are a lot of deep thinkers on here, smoking Haze strains helps me, lol. Growweedeasy,com is good place to go to also, it may not be all that advanced but it covers the basics in good detail and that usually leads to new idea's. 

               

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              • So if I interpolate the vdp graph I should be OK at 95/80 cool or even 100/85?

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                • Probably not, it depends on the leaf surface temperatures. What I look for is the Leaf VDP, I was not clear about that before sorry

                  The room temperature and the relative humidity tell you the room VDP. The room VDP and the leaf surface temperature give you the Leaf VDP. This ling has a calculator that. 

                  https://www.dimluxlighting.com/knowledge/blog/vapor-pressure-deficit-the-ultimate-guide-to-vpd/

                   

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