T5s chucking out a lot of heat?

[420Girl]

Hi everyone,

I have 2 northern lights autos (seedlings) in a 90x60x90cm grow tent with 2ft 4-way T5s at 96w. I read that T5s hardly chuck out any heat and can be placed literally centimetres above plants, so I figured they would be perfect for my relatively small grow space. I've found however that they heat up a lot, and therefore my whole tent gets too hot and my poor seedlings are suffering for it. The lights are currently a good 12" or more above them so I wouldn't dare put them only a couple of inches above them or they'd burn to a crisp!

Could my lights be faulty or is this normal? Perhaps I would be better off buying a 125w CFL w/reflector or would that get just as hot? My only 'ventilation' is opening the vent flap and a desk fan in the tent that is blowing the hot air under the lights away from the plants, but I think the overall temp in there is still too hot for them.

 

[Fuzzy Duck]

It is just your ventilation set up really which is at question !

Well hot/warm air risers it will build up creating temp issues so what you need to do is to rig up an exhaust fan at the top of the tent to remove the hot stuff whilst leaving your passive vents open to suck new fresh in & this will aid in temp control.


It is a pretty small tent more likely suited for cloning or keeping some small mother plants but perfectly fine for a micro grow staying with cfl or T5 through out the grow a hps/hood may provide total height limitations once ya think about hood size & safe hanging distance etc.

I'd more likely go down the route of a 4 inch inline fan set up out side of tent blowing through the carbon filter this will save some head room space other wise it is done the other way around if ya have room to play... that is more of expensive option with odour control tho.

If ya not worried about odour scrap the carbon filter & get a 4 inch inline fan, you may be able to improvise tho with stuff but you really need suitable air exchange to get the best out of ya grow.

 

[Piña Delores]

Hi 420 girl

T5's do indeed kick out some heat, I had 4 x 39w T5's and some LED's in my old grow space for my first grow (no journal). It was a shade smaller than yours by the sounds of things, and the heat was quite a challenge.

Extracting air from the top of the space was the key. Along with moving the air that sits under the light fitting.

I think the rule of thumb's you need twice the area for incoming air that you have for extraction. So a 100mm extraction fan will need, 2 100mm holes for incoming air.

Another thing I found useful was mounting the ballasts/drivers for the lights outside my grow space. They kick out as much heat as the lamps do. My light was very DIY though, not sure how easy that would be with a pre-built unit.

I have no personal experience, but I think you might end up worse off with a 125w cfl. It could end up being hotter in a more focused area.

Re-reading your OP, you mention nothing about extraction, that'll be key. You'd be better investing in an extraction fan than a new lamp. With that space it wouldn't need to be huge. I used bathroom extractor fans for my box, might need something more fit for purpose with a tent though.

Hope I helped



Feel free to check out my journal

 

[420Girl]

Hi guys,

Thanks so much for your input! I definitely agree and will be buying a 4" inline fan to extract the hot air. For the time being I've actually removed 3 of the 4 tubes in my T5 unit and that has really helped with the heat, and the light isn't overkill for the girls.

I'm hoping I can fit a fan to my tent okay since the sock is in the roof of the tent and not the side. I assume you can just put these things in the sock and pull the drawstring in to secure it?

Thanks again!

 

[bckush]

I run 10 55w twin tube t'5s with a 4inch fan and a Phat filter...no heat issues and my plants can get within a half inch or so as long as you have a fan blowing across the bulbs.

Hope that helps

 

[420Girl]

Wow, that's reassuring lol, thanks! If I can get anything remotely close to that with my 4 T5s I'll be happy

 

[bckush]

Wow, that's reassuring lol, thanks! If I can get anything remotely close to that with my 4 T5s I'll be happy

Although they say t5's aren't the greatest for flowering, I think I am having great results....could be all the watts worth though.

It will burn them if you let them touch the lights for very long