Just not cool

sbcomposer

sbcomposer

Member
I have a grow tent something like 36x36x72 in size. I placed it outdoors rather than indoors with the idea that it is MUCH cooler outside. Its under cover so no direct sun at all. Also nice and dry if it rains.

I got a 600w light that came with both a 600w MH and 600wHPS. Starting with 4 clones which are about 6" now.

I have one 6" duct fan blowing out of the tent, and a smaller desk fan inside.

I started with the MH bulb since I was told these are superior for the veg state. However this morning the tent temp was 93! And it was maybe 62 outside.

So I switched today to the HPS which I hope will not emit as much heat.

It seems you would need an actual AC unit in the tent to use the MH bulb?
 
torontoke

torontoke

Well-Known Member
The bulb type isn't the reason for the temps. U won't see much difference after you switch.
Air exchange is the most efficient way to cool the tent. However I've never heard of anyone using a tent outdoors.
Why use the tent at all why not just leave the plants outside and use the sun instead of a light?
Tents aren't waterproof either so won't the light and stuff still get soaked if it rains?
 
sbcomposer

sbcomposer

Member
The reason for a tent is to allow 24/7 light and speed up vegetation. Its also to allow a switch to 12/12 for flowering. You can't do that outdoors.

And it's MUCH cooler outdoors here then indoors. Why increase the heat by placing the tent inside? And as I said the tent is outdoors but under a waterproof canopy. Rain can't touch it.
 
torontoke

torontoke

Well-Known Member
Well inside you could run an ac run into the tent.
Either way you will probably need a two fans out one drawing the heat off the light and the other exchanging the air.
 
sbcomposer

sbcomposer

Member
Thanks Torontoke. Ill try adding another 6" exhaust fan and see if that helps. Everything I have read elsewhere says MH bulbs do run much hotter than HPS so I'll stick with the HPS.
 
S

shahomy

Well-Known Member
sbcomposer said:
I have a grow tent something like 36x36x72 in size. I placed it outdoors rather than indoors with the idea that it is MUCH cooler outside. Its under cover so no direct sun at all. Also nice and dry if it rains.

I got a 600w light that came with both a 600w MH and 600wHPS. Starting with 4 clones which are about 6" now.

I have one 6" duct fan blowing out of the tent, and a smaller desk fan inside.

I started with the MH bulb since I was told these are superior for the veg state. However this morning the tent temp was 93! And it was maybe 62 outside.

So I switched today to the HPS which I hope will not emit as much heat.

It seems you would need an actual AC unit in the tent to use the MH bulb?
Click to expand...
Is your light the open type?(no glass)...if so, i can see 93
The duct fan is worthless...get a real(centrifugal) 6" fan, and make sure your fresh air intake opening is large enough to allow fan to run wide open. And cover opening with screen to keep bugs out...cause they will come, being outside. I`d suggest some SNS209, it`s systemic, meaning it absorbs the stuff into its leaves and the bugs wont eat them...they leave! 20$ a bottle and you should be safe till harvest. I just use it during veg.
I`d also get an oscillating fan blowing across your canopy/right under the light
Replacing the duct fan with a real one should take care of most of the heat...
Are you worried about odor?
Never heard of MH being cooler than HPS, and can`t say i`ve heard of HPS for veg... i`d switch back
 
sbcomposer

sbcomposer

Member
shahomy said:
Is your light the open type?(no glass)...if so, i can see 93
The duct fan is worthless...get a real(centrifugal) 6" fan, and make sure your fresh air intake opening is large enough to allow fan to run wide open. And cover opening with screen to keep bugs out...cause they will come, being outside. I`d suggest some SNS209, it`s systemic, meaning it absorbs the stuff into its leaves and the bugs wont eat them...they leave! 20$ a bottle and you should be safe till harvest. I just use it during veg.
I`d also get an oscillating fan blowing across your canopy/right under the light
Replacing the duct fan with a real one should take care of most of the heat...
Are you worried about odor?
Never heard of MH being cooler than HPS, and can`t say i`ve heard of HPS for veg... i`d switch back
Click to expand...
Thanks for the great advice! You had the bulb thing backwards though - The MH is WAY HOTTER so I switched to the HPS.
 
sbcomposer

sbcomposer

Member
Took the great advice here and added a 2nd intake fan at the bottom for a total of 2, and a 6" centrifugal exhaust sucking out from the top. I also pointed the desk fan right at the light - which btw I switched back to the 600w MH. Temps have been between about 70f and 92f at canopy level - mostly around 80f. I added 2 clones a week later and as you can see those two aren't doing a well as the first two which are a week older.

The two on the left I am guessing what another 2-3 weeks before I switch to 12/12 and a dehumidifier?Growing in a 4x4 tent outside. Not sure to keep the righty's or not.
My naming convention for the pics:
L=Left R=Right RR=Right Rear RF=Right Front etc etc..
 

Attachments

killer_dabbins

killer_dabbins

Member
If you use a hepa filter you can connect your fan and use intake cool air from outside, or hepa filter on bottom of tent and exhaust at top will also draw in cool air.
 
You must log in or register to reply here.
Top