Negative pressure in grow tent
- Thread starter TUK5150
- Start date
With a reduction in space (with heat source of lights remaining constant) temps would increase.
I'm not sure if I commented on another of your threads earlier, but those temps (24/30C) aren't problematic...ideally they could be a few degrees lower, but not worth losing sleep.
Are your lights off during the hottest periods of the day? Does the extractor motor kick off more heat as it runs harder? Do you have a dedicated intake for the tent? Are the plants in veg? Wondering if you could open a rear tent vent to allow more air, but with minimal light exposure (in case you are going dark during the hottest periods)...but if you are in veg this wouldn't be a deal breaker...
I'm not sure if I commented on another of your threads earlier, but those temps (24/30C) aren't problematic...ideally they could be a few degrees lower, but not worth losing sleep.
Are your lights off during the hottest periods of the day? Does the extractor motor kick off more heat as it runs harder? Do you have a dedicated intake for the tent? Are the plants in veg? Wondering if you could open a rear tent vent to allow more air, but with minimal light exposure (in case you are going dark during the hottest periods)...but if you are in veg this wouldn't be a deal breaker...
- Thread starter
- #3
Hey man yeah I think you may of on my heat issues, but yeah there not really a problem as of yet as summer is only just hitting, I can see it getting quite dramatic in budding, I am currently still I veg have another 3 weeks left or so until I flip them, my lights run on the coolest period in the day so for 18 hours I do 6pm on and 12pm the following day off then off for 6 hours till 6pm then back on again, the temps are only increasing an hour before lights on from 22c to 24c, and increase from 24c lights on to 30.0c until the sun gets off my room then it all settles down perfectly to 28.5 as I set it to, it's just those 2 hours or so of heat rising I want to stop, opening a vent when lights off isn't really an option as light will leak directly in onto the plants opening a new can of worms which I don't need right now, I just wish for things to go smoothly for my first time lol
But yes I do also have just an intake ducting built to a vent to the window sucking directly from outside, which sucking hot air in won't help but that's my only option really as it's in a bedroom
What are the temps if you left the extractor on medium and try to avoid the tent sucking in? Two (2) hours of peaking temps aren't a deal breaker...
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- #5
If I leave it it settles lights of 23.5/8c then lights on within minutes it's 30.0c for an hour or so then for the rest of the period it's perfectly fine....maybe I'm just worrying to much as a newbie, I just don't want to end up with shitty pond weed in the end when ive put alot of time effort n money in so far lol, my last resort is an Air cooler in the room itself where the tent is
Bush Doctor 77
Well-Known Member
Warm temps aren't always a problem. As long as you have plenty of fresh air moving across the leaf surfaces, they should be OK. This weed grows very well in some of the hottest climates in the world.
- Thread starter
- #7
Well I just got back and my lights off temps was 26 degrees c!!!! So put a frozen bottle of water down the duct on the inside of the tent to cool the air coming in temporary, got it down to 24 degrees in there now it's driving me crazy, I think it's going to have to be air con
Greenlizard
Well-Known Member
High temp of 30 degrees... I wouldn't sweat it. No pun intended. You are over thinking things. As already mentioned this plant grows in very hot places around the world such as Afghanistan and do very well. As for loosing space due to negative pressure… That's just the nature of growing in a tent. I find it helps support the heavy buds in late flower. You could just open a vent and shove a piece of flexible ducting through it and put a few "S" turns in it so it doesn't leak light. This will reduce the negative pressure a bit but also allow more airflow and aid in reducing the temps. It may also increase the lifespan of your exhaust fan by reducing the draw resistance.
Or do nothing and still enjoy some great bud!
Or do nothing and still enjoy some great bud!
What he said^^^
Your exhaust fan can't work like it should if there's restricted airflow into the tent.
You definitely need to do as @Greenlizard suggested-it will help with heat removal
and lower the negative pressure in the tent
Where is your temperature sensor mounted? It should be at canopy level.
falstaffo
Well-Known Member
i had spikes of 35c a couple days ago..
30c is fine
im on the case to try and combat the rising summer temps too lol not too worried though atm.
30c is fine
im on the case to try and combat the rising summer temps too lol not too worried though atm.
- Thread starter
- #11
Haha I love how chilled about the situ you are haha I need some of that stuff your smoking lol!!!High temp of 30 degrees... I wouldn't sweat it. No pun intended. You are over thinking things. As already mentioned this plant grows in very hot places around the world such as Afghanistan and do very well. As for loosing space due to negative pressure… That's just the nature of growing in a tent. I find it helps support the heavy buds in late flower. You could just open a vent and shove a piece of flexible ducting through it and put a few "S" turns in it so it doesn't leak light. This will reduce the negative pressure a bit but also allow more airflow and aid in reducing the temps. It may also increase the lifespan of your exhaust fan by reducing the draw resistance.
Or do nothing and still enjoy some great bud!
I think my idea is now....tomorrow as it's pay day, go get some side support to force the tent from sucking in that should inline help suck more air in from the intake duct, but also up the intake duct from 6inch to 8 or 10 inch? If that doesn't work how would you think about placing an air cooler in front of the intake end of the duct? Essentially sucking the cool air directly from the air cooler, but also still sucking the fresh warmer air from my bedroom? To lower the temps slightly? All of which will reduce my fan speed, hopefully decrease the temps and improve air flow? Is my way of thinking wrong? Or am I missing something? Would any of the above cause anymore issues?
- Thread starter
- #12
Yeah man I am gunna give it ago with bigger intake ducting and see if that works, I'm just losing my head trying so many different things, all my probes are at canopy level yes
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- #13
What are your running hours mate? What's your lights on n off temps? At it's hottest and for how long?
LiberalThinker
Well-Known Member
You could put a fan on the intake vent blowing in and that would speed up overall airflow for cooling and relieve negative pressure.
- Thread starter
- #15
As in just like a little fan like you would have blowing over the canopy etc? Just wedge it in?
LiberalThinker
Well-Known Member
I would get one with the same flow rate as your extraction but if you already have that give it a whirl.
- Thread starter
- #17
Ahh so you mean like a proper fan the same as my extractor but turned round? I thought about it but it's not really needed plus noise is an issue as it is lol
falstaffo
Well-Known Member
it was 9pm-4pm 19/5
9pm-9am 12/12
bringing the 19/5 forward an hour a day tho, want to get it to 6pm-12pm so its off from midday to eve.
never check off temps
on temps 24-28 usually, but yeah has been hitting 30 a fair bit on hot days.
LiberalThinker
Well-Known Member
Yeah, noise is not a minor issue. The other way to reduce the negative pressure is to have intake hole/s big enough not to cause it or open the door a bit when light's on.
