400W small grow tent heat/ventilation question! Please help before she gets baked! :)

[kryptoniteglo]

Hi Folks,

Thanks in advance for your advice. I just set up a 400W small grow tent -- standard stuff. And I put my 2 week old seedling in a bubble pot, and she's in there now with a MH light about 18 inches above her.

My question is one of heat -- I've got all the vents open AND the door half open because the temperature really rose in there! With the door fully zipped, it's low 90s above the reflector and close to 100 underneath (where the seedling is). With the door half open, it's about 87 above the reflector and 95 underneath.

I have the inline fan exhausting air, and the clip on fan down by the pots circulating air at seedling level.

Is it typical to have the door unzipped while the light is on? Or should I be able to maintain a lower temperature with the door fully closed?

I live in a studio apartment, so if I have to leave the door open, it just pulled me off the 24-hour schedule for veg into 18/6 so I can get some sleep! Geesh that light is bright! But I think with the door closed all night, it would be in the 100s in there by plant level.

Is there anything else I can do to cool it down?

Thanks!

 

[James and Elsie]

Hi, Kryptoniteglo.

We're having the same problem, and if you look at the thread we started yesterday, more cooling problems , you'll see a number of suggestions. It's kind of looking as if we're going to need to get a cooled light, but before we take that step we're going to try an in-line in-duct fan to actively duct cool air in through the lower port in the tent. If you come up with another solution, please let us know.

Thanks, and good luck!

 

[kryptoniteglo]

Thanks James and Elsie,

I read your thread with much interest! And I do think this might be better to do in January...but I'm going to push forward as best I can. I'm leaving the door open during the day 18 hours, then turning the light off, letting it cool for a bit and going to bed. Hopefully she'll make it...and if not I'll just start again in January.

Thanks!

 

[mr2shim]

I swear I'm going to beat my head against the keyboard if I have to read another thread dealing with heat issues. It's simple, amazingly simple. Your tent will NEVER, EVER be cooler than the ROOM it's in. If the room the tent is IN is 100 degrees well by golly your tent will NEVER see temps lower than that. See where I'm going with this?

FANS don't/won't/aren't going to cool air. They MOVE air, simple as that. IF you are having cooling issues the solution isn't to buy bigger fans NO. The solution is to get something that cools air. What does that ladies and gents? Air conditioners.

 

[kryptoniteglo]

Hi Mr2shim,

I hear you! My room is air conditioned at 76. My comment about January is that I could open my windows and get the room nice and cold when I'm not here. The other issue is that the AgroMax tents have a design flaw that impedes moving air enough for a grow -- the only small vent at the bottom is more appropriate for electrical cords, not an intake fan.

James and Elsie,
I just tried an experiment -- unzipped the tent from the bottom and put a Vornado room fan on low to push cool air in. I also blocked up the gap with a box to keep my cats out. It worked! Inside temp under the light is now 85. Sweet!

The only problem is that I can see some cat hair now flying around the tent. But now that I know this works well, I'll figure out a screen system before the plants get sticky. A cheap fix, just the way I like it.

KG

 

[James and Elsie]

Thanks, KG.

We're doing something similar, and it's working for now - we'd just like to be able to keep the tent closed. I'm glad you've found a solution - just don't grow any catnip!

mr2shim: we hear your frustration, and agree that fans just push air around. In our case (and, it sounds like, KG's), the air in the room is cooler than the air in the tent, so blowing the cooler air in helps.

 

[kryptoniteglo]

Thanks, KG.

We're doing something similar, and it's working for now - we'd just like to be able to keep the tent closed. I'm glad you've found a solution - just don't grow any catnip!

mr2shim: we hear your frustration, and agree that fans just push air around. In our case (and, it sounds like, KG's), the air in the room is cooler than the air in the tent, so blowing the cooler air in helps.

The reason I got the tent was to protect my hard work from plant-chewing felines. I'm going to call HTG to see if the small 4" inline fan will work, so that I, too, can keep the tent closed. But if not, I'll just find a way to make my fix a little more elegant.

Good luck to you! Looking forward to your harvest pix.

 

[mr2shim]

4" inline fan works for cooling down my 400w. My tent is fairly small too, 36"x20"x60". I have an a/c running in the room the tent is IN to keep temps down. If I didn't the tent would get really hot. Also exhausting the heat into a DIFFERENT room helps. Dumping hot air into the room your tent is in will make the tent hotter which will make the room hotter. Rinse, repeat.

 

[kryptoniteglo]

4" inline fan works for cooling down my 400w. My tent is fairly small too, 36"x20"x60". I have an a/c running in the room the tent is IN to keep temps down. If I didn't the tent would get really hot. Also exhausting the heat into a DIFFERENT room helps. Dumping hot air into the room your tent is in will make the tent hotter which will make the room hotter. Rinse, repeat.

Thanks for the 411 on the fan. Roger on the a/c in the same room as the tent. That's what I've been doing all day with my McGivered set up, and the temps have been mid-80s without fluctuation.

 

[pro5imian]

whats the word on that HTG 4" fan?? i need to get a inline before i start up and was looking at that one or the 6"... but for that price iam think'n its gonna be noisy as hell

 

[Bling Bling BC]

u must get a inclosed hood with a inline fan of at least 700 cfm's ( cubic feet per min) i recommend vortex fans quiet high powered perfect FRESH AIR INTAKE MUST BE DRAWN FROM COOLER PART OF GROW ROOM eg. under the floor next room outside but Not from same room!! misting also helps cool then air.

 

[Hogg]

u must get a inclosed hood with a inline fan of at least 700 cfm's ( cubic feet per min) i recommend vortex fans quiet high powered perfect FRESH AIR INTAKE MUST BE DRAWN FROM COOLER PART OF GROW ROOM eg. under the floor next room outside but Not from same room!! misting also helps cool then air.

This is overkill if you put a inline fan with 700cfm in that size tent it would suck the sides in and cave-in the tent....You need a good inline 4inch either 160 or 190 cfm and vent into a different room or outside. Also, investing in a cool tube would really help. BTW when I say inline fan I do NOT mean a booster fan like the ones on ebay for $25.00, I mean a real inline fan pushing a real 160-190 cfm constant. Ebay has the fan/filter combos in the $100-$120 range..Good Luck