Need help with heat!

[Scrizzly]

Hey everyone,
I’m in process of first grow and just transplanted my plants into 5 gallons yesterday. For the first month and a half of their lives they were under 1 600 wt metal halide. Since transplanting though I needed another light so they can be more spread out.

I have 2 600 watt metal halides on in my 8x4 grow tent now. But that shot my temperature up from mid to high 70s to 87-92 degrees!

I need to lower temperature ASAP.
I’m in Canada so venting outside right now isn’t a option as during night temp will get to the negatives and kill my plants.
My lights are air cooled and the vent runs out of the room but still gets too hot.

I’m thinking about venting into my attic but just curious what people’s thoughts are on that.
I own my own home so don’t mind breaking through the drywall but what I am worried about is the hot air and humidity causing mould problems in attic.

Has anyone ever done this for multiple grow cycles and ever had a problem?

Other option is AC but I’d prefer not to spend $400 on a AC right now plus the added hydro cost.

Any thoughts?

 

[TurboBucket]

Why do you refuse to vent outside? Your bathroom is likely vented outside does it freeze? (If it does check your outside dampers)

Is this in an extra room with the door closed? Or in a living room? Does the temp in the room around the tent increase now with the second light?

If the tent held 70s before the second light it sounds like your starving for air or the surrounding air is too warm.

Don't vent it into your attic. Bad idea as you already noted.

 

[Mars Hydro]

Why not change to LED grow lights? Maybe for just one first, and then you will see the difference.

 

[Icemud]

These aren't cure all's but a few suggestions:

***Can you move ballasts out of the grow area?
***Are you running your daylight cycle during daylight hours? If so, try running your (plants daylight cycle) at night which may help cool the grow.
***Vent outside
***Crack a window very slightly so the air exchange between your room and outside helps cool air

 

[Leopold Bloom]

I run my lights at night for the same reason that way I don't have heat issues what size is ur inline fan

 

[dr.h00k]

...Ice makes good suggestions...getting the ballasts out of the tent would make a big difference if possible...if not, gotta' cool the room, or vent outdoors...cheerz...h00k......

 

[Aroxol]

Short of intaking that cold air, exhausting to outside with high CFM fan, introducing A/C, or changing to LED... I don’t think you’re going to solve the problem, unfortunately. I’ve had my fair share of heat problems and spent way too much time on “what if” solutions, just trying to save you time and energy. Bottom line, there’s only certain things that work, and they’ve all been stated in this thread.

 

[EhCndGrower]

As a fellow Canadian grower I too had to figure how to cool my tent in the late flowering stage that just finished a few weeks back. I went and bought some 4” ducting line (probably go bigger for your bigger tent) and fed one on one side of tent near the top and fitted a stocking over the ends to keep bugs out. Then I took another 4” ducting and repeated the above on the other side of the tent going into a bottom vent area. I then cut a hole into a piece of styrofoam that would fit the ducting and fill out a window in the basement. (Much like an old window air conditioner) It kept the real cold air out of the basement but took my temp down in the tent to the low 70’s. I had at one time 8 plants in a 4x4 tent and my new quantum board on full power, so the temp would reach low 80’s before my little MacGyver experiment

 

[Skybound]

I've been venting to the attic/crawl space for a couple years and never got any mold. You can see my duct stabbing through the ceiling, and into the attic where I have it connected to 2 fan/filter combos, but before the extraction, I have another T to a 4" vent that sucks off of the veg closet. So there's a Veg, and 3 - 4x4 bloom rooms being sucked by 2 - 440CFM fans. I started out also with a 600w HPS in each, but in the northeast USA, summer temps were simply unmanageable, so I ditched the HIDs and built some COB LED fixtures. With HID, you do need active cooling unless in large well vented and circulated rooms. I also used to run a separate vent circuit from and to the same room, but straight through the cool tubes so not to contaminate with stinky air. Overall, HID is just too much of a pain in the ass to extend all of the extra effort, you can only get 2,000 - 2,200k bulbs, most of the electricity you pull from the wall is converted into heat, not light and the expensive bulbs needs to be swapped out pretty frequently. As soon as you can, invest in some LEDs. I have pretty good results with COBs, but I hear great things about quantum boards as well.

 

[Scrizzly]

Hey everyone thanks for the input.
I’ve taken my vent for the air cooled lights and ducted right outside. I put one of those things on the other end that closes the vent when air isn’t blowing through it.

I have a 8 inch fan pushing the air.
Plants seem to be liking the slightly cooler temps. It’s sitting at 79 degrees right now but it was even lower earlier today. Going to measure the temp in the morning before lights turn on and see what the temp is at night.

One more question. What would be the lowest temperature recommended for at night? I’m thinking it’s probably going to drop to 65-70. Do you think that will be fine?

 

[Skybound]

High 50s for the low. It's not ideal, but manageable.