Grow Room Options- roots and leaves

MNXR250R

MNXR250R

I have options in a grow room that I'd like some feedback on. It's a small bedroom that is roughly 12x9 feet (just over 108 sqft). I can vent in or out (from/to the outdoors).
 
Currently I have two grow tents in this room. One is 2.5ft x 2.5ft at about 6ft tall. The other is a 4ft x 2ft shorty. Both are vented with Hurricane exhaust fans (to the outside). I've had some success in the tents, especially with seedlings and small plants all moved outdoors).
 
I want to grow peppers indoors from seeds to full maturity indoors and all year round.
 
Lighting: Most of the fixtures I have are T5 (2ft x 4 lamp, 2ft x 8 lamp, and 4ft x 8 lamp...all 6500K). I also have a new LED (VIPARSPECTRA PAR700).
 
The first question I have is whether or not to continue to grow in tents (rhetorical question). I can completely overhaul this room for growing. However, it is also my personal play space (i.e Computer room, Chemistry room, Electronics room, storage room etc). If I can increase the humidity in the room for peppers like the Bhut Jolokia (mid temp high humidity) it may as well destroy my electronics and other cool things in my room.
 
If I stick with tents, I have a problem of maintaining the internal environment of two or more tents... multipul environments. Not easy.
 
My house has A/C. In the summer months while the A/C is on, the indoor humidity is around 40%. In the winter months while the heat is on... it can be even lower. I need to add a humidifier for sure. Also I can't control the grow room temperature with home A/C as my wife won't allow me cutting into the floor/walls :)  )
 
So then we get to the meat of my inquiry...
 
I have read that keeping the roots relatively cool even if the leaf temperature is much higher is more or less... natural.  So then, if I can create a system where the roots remain at 70-75degF (room temp) while the leaves get to...85..90..or more degF ... all should be fine ????????? (nutes aside)
 
I would appreciate your input. I would also like to have information to support or refute my understanding.
 
Thanks, Jeff
 
What you're saying makes sense but, in an indoor environment the root system will always be cooler than the leaves. The pots are under the canopy and the canopy receives the light plus whatever heat comes along with it. Not to mention ventilation and fans causing evaporative cooling of the soil. BUT, with your tents being so small, any kind of exhaust fan is going to completely destroy your humidity. If you're going to do tents then get bigger ones. The light fixtures you have wont even fit your tents so it sounds like your hands are kinda tied anyways.
 
Maybe I should restate my question.  In a tent, eventually the whole plant (leaves,roots,pot,water) will become equal to the temperature inside the tent... agreed.
 
My question is more like... what if I keep the root system OUTSIDE of the tent (to control root temps)... then I shouldn't have to vent so much heat and humidity. Can the peppers tops survive or even thrive at higher temps like 90+  ???
 
I know that roots do not like being too hot.  But I'm wondering if the leaf system feels the same about the heat ?
 
Thanks, Jeff
 
MNXR250R said:
Maybe I should restate my question.  In a tent, eventually the whole plant (leaves,roots,pot,water) will become equal to the temperature inside the tent... agreed.
 
My question is more like... what if I keep the root system OUTSIDE of the tent (to control root temps)... then I shouldn't have to vent so much heat and humidity. Can the peppers tops survive or even thrive at higher temps like 90+  ???
 
I know that roots do not like being too hot.  But I'm wondering if the leaf system feels the same about the heat ?
 
Thanks, Jeff
Click to expand...
I dont think it would be a problem.. I live in an area where its been anywhere between 98 and 103 lately during the day and my plants are producing great. But some varieties do better with heat than others. All my plants are syrian heirlooms so they tolerate the heat well. Ive never seen a system where the root system is outside of the tent but it sounds interesting and i dont see why that wouldnt work. I suppose its kinda the same way hydro works in that sense. They usually keep the root temp between 68 and 72. I say go for it.
 
As the plants get large enough they will make humidity due to transpiration. Get speed controllers on your exhaust fans so you can dial them down some to keep more humidity in the tent, if needed. It may take a few adjustments to find a happy medium between temp and humidity. Also the hotter the tent is, the more the plants will transpire (ie make humidity).
 
Good Luck, Happy Growin'   :P
 
Edmick said:
I dont think it would be a problem.. I live in an area where its been anywhere between 98 and 103 lately during the day and my plants are producing great. But some varieties do better with heat than others. All my plants are syrian heirlooms so they tolerate the heat well. Ive never seen a system where the root system is outside of the tent but it sounds interesting and i dont see why that wouldnt work. I suppose its kinda the same way hydro works in that sense. They usually keep the root temp between 68 and 72. I say go for it.
Click to expand...
 
Edmick...  Yes, like a hydro system with a chiller.  I'll be using soil so a chiller in the conventional  sense won't work.  I'll have the grow bags under the tent and have the plants grow up and into the tent. 
 
hogleg said:
As the plants get large enough they will make humidity due to transpiration. Get speed controllers on your exhaust fans so you can dial them down some to keep more humidity in the tent, if needed. It may take a few adjustments to find a happy medium between temp and humidity. Also the hotter the tent is, the more the plants will transpire (ie make humidity).
 
Good Luck, Happy Growin'   :P
Click to expand...
 
hogleg.. I have speed controllers on the fans.  I've been using them to control the HEAT only.  I'll back them off a bit and see if I can get the humidity up.
 
Thanks All.
 
Jeff
 
Had a change in plans.... or should I say that my Wife had a change in plans :)
 
I was given permission from her (my wife...  Happy Wife Happy Life)... to move my grow... and that is everything !!... to the basement !!!!  YES !!!
 
It had been a challenge to explain the basics of heat, humidity, photosynthesis and respiration to her, and how difficult it was to control those aspects in my upstairs workroom.... so I changed course. I simply told her that I would have to spend $500 to $1000 or many more dollars to control the heat and humidity in the upstairs bedroom/workroom. It was that...or I could move everything to the basement and use the naturally cool air (and higher relative humidity) at nearly $0.0 ...  She was slow to agree, and I had to promise a few special projects for her, but in the end  get a nearly constant supply of 68deg (F) at 60 percent RH.   How awesome is that ??  Yes !! It is Awesome !!!!!!
 
I had struggled and struggled to vent the heat and keep any humidity in my grow tents upstairs. I tried sucking cool air from the basement, adding humidifiers and fans to circulate the air. Nothing I did would keep the air temps under 88-95degF inside of the tents, and I could never get the RH above 40%. Fortunately for me, now I don't have to spend a lot of cash to invest in an A/C unit and CO2.
 
Sometimes... the wind is favorable :)
 
Jeff
 
 
Update... 
 
I have completely moved to the lower level. The ambient temp is 67degF with a RH of 38%.  
 
My target is to have a temperature inside of the tent in the range of 70-80 degF. I figured that sucking the cool 67 degF air from the basement would make that hope a reality. Fact is.... it didn't. I was still getting the temps in the low to mid 80's... which was closer to my target, but not what I expected. I tried moving more air but I didn't get the temps I'd hoped for.
 
During this process I noticed something. I guess it would be a DUH!!! to some but I didn't know...  As the temperature inside the tent increased, the Relative Humidity readings DECREASED.
 
So I Googled.... I found info on the relationship between temperature and humidity and then tried something. I added a humidifier to my tent (did this before but in the upstairs grow where the ambient temp was 76 degF.... but thats another FAIL story).
 
As the humidifier pumped water vapor into the tent, I watched the temperature inside of the tent DECREASE ! And, without ANY venting ! (The temp decrease wasn't like having an A/C unit installed, but it went down :))
 
Progress !!  So then... the more water vapor in the tent(humidity), the more energy (heat from the lights) it takes to increase the tent temperature. Plus, the added humidity increases thermal conduction to the tent material increasing the internal heat dissipation away from the tent. And even more, who doesn't like humidity ?
 
73,
 
Jeff
 
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