Cooling questions

Lurkdewitt

Well-Known Member
Hey guys, I've been battling high temps in my tent since I put it up yesterday. It's a 2x4x5 Mylar lined tent, I have an open hood 400 watt hps, and I'm running a 240 cfm inline fan and my intake is passive but my temps run between 86 and 90 degrees. Can you take a look at my setup and see if you see any reason for my temps to be that high? I added a desk fan, and it only dropped the temps 1 degree. The ambient temp in the room is 76.. Help me out before my little autos come up! Also I'm not running co2 and we have no AC in our apartment... Thanks :bigjoint::bigjoint:
 

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Dude I;'m in the same position as you, battling summer heat for the girls. I'm holding steady @ 84 right now though with a high speed fan blowing the tops of my plants. I figure its like being out in the sun..with a breeze it feels great but no breeze and starts to suck. So I think they'll be alright in the heat with a good breeze across the tops. If all else fails, if you have a dimmer just turn it to 75% or 50% and put it back up when it gets cooler. Or raise the light. gluck
 

Lurkdewitt

Well-Known Member
Thanks man, I guess I'll just wait and see how they handle it, hope the little seedling will survive and not get stressed! Good luck man, winter is just around the corner!;-)
 
in winter it'll be so easy lol...what auto seeds are you starting? I've got some herijuana fems and some jackberryxmadscientist just getting going now along with some nirvana randoms.
 

Bear Country

Well-Known Member
Hey guys, I've been battling high temps in my tent since I put it up yesterday. It's a 2x4x5 Mylar lined tent, I have an open hood 400 watt hps, and I'm running a 240 cfm inline fan and my intake is passive but my temps run between 86 and 90 degrees. Can you take a look at my setup and see if you see any reason for my temps to be that high? I added a desk fan, and it only dropped the temps 1 degree. The ambient temp in the room is 76.. Help me out before my little autos come up! Also I'm not running co2 and we have no AC in our apartment... Thanks :bigjoint::bigjoint:

Its hard to control temp in a tent like that, in an apt. One of your problems is that you have that open hood 400W HPS....HPS are some heat producing suckers. You really need a sealed light fixture. Are you running AC in the APT? If you could get a sealed light fixture, I would get that tent and the duct wk as close to the AC register so that you could pull the coolest air through that light as possible....then carry the exhaust as far away from your tent as possible. Look...your ambient temp is already at 76 degrees....thats already pushing optimum temp for cannabis....now your adding 400 watts of HPS to a sealed grow tent....thats basically an oven. Sealed light fixture, coolest air possible blowing over that light and carry the exhaust as far away from that room as possible. Be creative....even a small portable ac unit that you can dedicate to the light and the room the tent is in....to lower the ambient temp even more...Apts are tuff...its not like you can cut holes everywhere...good luck bro!

Bear
 

Lurkdewitt

Well-Known Member
in winter it'll be so easy lol...what auto seeds are you starting? I've got some herijuana fems and some jackberryxmadscientist just getting going now along with some nirvana randoms.
For now I'm running Biodiesel mass and skunk mass, can't wait because their both crosses with critical mass! This is going to be my first indoor grow so I'm going to start small, plus I gotta hold off on till this October when my buddy's going to be running Some TGA genetics and he's gonna hook me up with clones. Hopefully I'll have a DWC system up and have good temps by then lol. Let me know how the jackberryxmadscientist is! Just the name has me intrigued haha.
 

Lurkdewitt

Well-Known Member
Its hard to control temp in a tent like that, in an apt. One of your problems is that you have that open hood 400W HPS....HPS are some heat producing suckers. You really need a sealed light fixture. Are you running AC in the APT? If you could get a sealed light fixture, I would get that tent and the duct wk as close to the AC register so that you could pull the coolest air through that light as possible....then carry the exhaust as far away from your tent as possible. Look...your ambient temp is already at 76 degrees....thats already pushing optimum temp for cannabis....now your adding 400 watts of HPS to a sealed grow tent....thats basically an oven. Sealed light fixture, coolest air possible blowing over that light and carry the exhaust as far away from that room as possible. Be creative....even a small portable ac unit that you can dedicate to the light and the room the tent is in....to lower the ambient temp even more...Apts are tuff...its not like you can cut holes everywhere...good luck bro!

Bear
I'm going to check out craigslist for a small window AC. I would just buy a new cool tube hood but I got my 400 watt fixture for $20 and a water bottle of jäger, so i want to make atleast one run with it haha. I'll figure something out, I almost think my cheapie thermometer is giving false temps because the top is black and heats up gradually. Also the I physically can't feel the difference between the room and the tent with the HPS on.
 

Bear Country

Well-Known Member
I'm going to check out craigslist for a small window AC. I would just buy a new cool tube hood but I got my 400 watt fixture for $20 and a water bottle of jäger, so i want to make atleast one run with it haha. I'll figure something out, I almost think my cheapie thermometer is giving false temps because the top is black and heats up gradually. Also the I physically can't feel the difference between the room and the tent with the HPS on.

Make sure your temps are accurate. There are allot of ways to fuck up any grow but high temps is one sure fire way to do it. Like I said...look for ways to be creative. Winter....your situation will be a bit more favorable to you but if you want to grow indoors in summer and you live i an area that is HOT to begin with, then you definitly have to work towards controlling your micro enviorment....thats key for any grower! Start slow bro...invest in a nice sealed light fixture, then when you can add another componet to your set up and take it like that until you have created a close to perfect micro climate....the rewards will more then make up for your investment with one or two good grows!!!! Luck buddy!!
 

duster74

Well-Known Member
I'm in a similar situation as you. On your exhaust, can you vent out of the room that the tent is in? By the looks of it, your duct work ends near the bottom of the outside of the tent, thus recirculating the hot air produced from the bulb in that same room. These tents are not 100% sealed so you are definitely drawing some of that some warm air back into the tent. Try and vent out into a nearby room, bathroom or laundry rooms work great! Also, if you aren't already, have your light cycle on during the night hours and pull your fresh air from a nearby window. This is what I do, and it works pretty good. As for an AC unit, get a portable AC unit, not a window unit. They're more efficient and you can direct the cool air from the AC directly into your tent much easier than a window unit. Hope this helps!
 
The small window ac would work good ...I cant do because they don't fit my window, maybe if I shove the exhaust up to the screen it could but itd prolly just exhaust heat into my room. A cooltube is definitely worth it for ya later grows. The 84 im at is like 7 degrees above ambient temp with the light 12" above the tops with cooltube. haha I've got the same thermometer and im kinda dubious about the temp readings too but I just figure I cant tell the 7 degree difference. The best advice Ive heard is to hold your hand at the tops of the plants and if its too hot for your hand its too hot for the plants then raise the lights or get more air blowing on it. The worst part of it all is the constant watering lol
 

Sire Killem All

Well-Known Member
get 6" plastic drain pipe the kind with holes on 1 side. Paint it white and extend ur ducting with it to the light fixture so it pulls more of the heat from lamp before it radiates to the plants.... jus a macgyver type idea, should help tho i think as the hole will pull from top while the end pulls more from the lamp as that is the heat source.

Edit: 4" drain if thats what ur running.
 

Lurkdewitt

Well-Known Member
Duster, I would get a small portable cooler, but since I moved from Colorado where any humidity is rare to north western oregon where on "dry days there is still 30% humidity so I think it would be ineffective up here.:/ I'm going to move my tent over by my window and run at least my exhaust out the window, and see if that will help.

bear country, I'm going to keep looking into a good air cooled hood, and more than likely ill end up breaking down and buying one soon lol.

Blaze, I'm gonna grab an old school thermometer tomorrow from Home Depot and se how accurate our little cheapies are haha. I'll PM you the results!
 

Lurkdewitt

Well-Known Member
get 6" plastic drain pipe the kind with holes on 1 side. Paint it white and extend ur ducting with it to the light fixture so it pulls more of the heat from lamp before it radiates to the plants.... jus a macgyver type idea, should help tho i think as the hole will pull from top while the end pulls more from the lamp as that is the heat source.

Edit: 4" drain if thats what ur running.
i put my ducting as close to the top as I could thinking all the hot air would rise but I'm gonna go pull it down a bit more closer to the light! Thanks for giving me an Ahhh Haaa moment Killem!
 

333maxwell

Active Member
For the next few weeks, you don't need anything more than a 25 watt 6500k cfl on each of them.. that will cut down on heat and be much more efficient.. buy you some time to figure things out. WAY to early to be having that kind of light on seed that is barely breaking dirt.

just one thought anyway.

Peace~
 
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