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Growing in the Tropics - heat, humidity, LEDs, etc

centralamerica

centralamerica

Member
Total noob here. I'm an expat and want to do a little indoor cloning & vegging here on the Caribbean coast of Central America. Air temps vary between 29ºC - 31ºC (80ºF - 90ºF) and humidity varies between 70% and 90%.

I have set up a grow room 12.5' x 12.5 feet (about 1400 cu ft or 40 cu meters), painted flat white, lightproof, and a friend has loaned me two 600 w HPSs (one digital, one analog), and a 400 w MH. They all have round parabolic reflectors (not vented). I've installed two vent fans that are each rated at moving 85 cubic meters (3000 cu ft) per hour, and two inlet ducts.

Of course, the room is getting like an oven. With just one 600 w HPS the temp is around 93ºF. I've currently just cut back to just the 400 w MH and have it off for the 6 hottest hours of the day, and the temp is around 83ºF now, but of course I'm in a pinch since I'm ready to transplant about 40 clones.

Questions:

Does anyone here have experience with indoor growing under tropical conditions? Any tips or suggestions from your experience you could share?

I imagine it's not going to be possible to lower the temp sufficiently without air conditioning (?)

Perhaps I should consider using LEDs instead to control the temps instead of artificially battling against the already warm air entering the room (?)

Any other insights or suggestions - I'm all ears and extremely grateful...

Hasta próxima from the jungles of Central America....
 
Z

Zapata's Dog

Member
Hey, I just joined this forum 5 minutes ago because I'm in almost exactly the same situation as you- I'm on the Pacific. My room is 4 x 8 feet, I have 2 x 400 MH and 2 x 400 HPS.

From my research I came to the conclusion that it would be impossible to grow under lights without air conditioning- I don't think it would even grow well outside here! According to Cervantes production suffers over 90 f. So I bought a little AC unit, and it was great with one light, but now I set up a second and it's working all the time to keep it at 80 f. It will clearly be no match for a four lights.

It's radiant heat- when I open the door I get a blast of cold air, but under the plants the thermometer says 80f.

Also, I'm using the lights just with the reflector- it came in an aluminum manifold with the ballast included but it weighed a ton (it's for for stadium lighting or whatever, nobody in this country sells lights for growing), so I rewired it so the ballasts are outside the room, just the bulb and the light aluminum reflector inside ... but I took the glass out too and that made a huge difference. I just did an experiment- a thermometer 6 or 8 inches under a 400 HPS: 160f with glass, 180 without.

So, first I'm wondering if anyone knows about glass and how much heat it reflects vs. light... obviously it cuts a lot of radiant heat, but how much light am I losing?

I think I'm going to have to vent the hot air from the lights separately, I guess using the aluminum manifolds (minus the ballasts) and cutting holes in them and attaching dryer duct and fans... I mean, not just to keep the temp low enough to grow but also to save on the AC bill...

So, to the thread starter, I'd say AC is a must- also for humidity.

To everybody else... any advice?

Zapata's Dog
 
206

206

Well-Known Member
I'm a big LED proponent, just want to get that out of the way up front. I would recommend you guys invest in a 90/120w LED or even 300w if you can afford it...your heat problems will disappear as they have almost no heat signature.

I currently own a 400w HPS and it sits in my basement, waiting to be used for the first time. I went LED-only after reading one insightful thing about HPS' during my research: A 400 watt HPS light is only about 35% efficient, which means that only 35% of the electrical energy delivered to the bulb is converted into light, with 65% converted into heat. EDIT: Not to mention all the heat emitted from the ballasts.

Just sayin...people with extreme heat issues have all the more reason to atleast consider LEDs...
 
Z

Zapata's Dog

Member
Well, I'm really interested in LEDs, they're clearly the future of illumination in general.

One issue would be acquiring them down here. I'd have to ship it and pay an absurd protectionist duty...

The other thing is- do they really grow top quality bud? I certainly don't know, but it seems from forum posts that most people think they do not.

Surely there are some objective controlled studies out there... anybody know?

Maybe you or someone could point us to some LED resources.
 
Treeth

Treeth

Well-Known Member
Well, If you got 40 clones you should probably invest in a closed air system just for the lights, a la cool tubes, meaning new fixtures.

probably really should get one of those indoor ac units, like from mitsubishi, to counteract the unruly humidity and temps...

or Get a c02 set up and 90 suddenly becomes bearable...

but damn any solution is gonna be energy intensive, or expensive, or both.

If only you could finish em' outside!

oh, and Low wattage leds don't equal top bud.

Don't you have like a patio you can get them to?
 
Treeth

Treeth

Well-Known Member
Vive Zapata!

Ok, theeeeeen just relocate to chiapas!

No "hell"/punishment down there...

you won't need no stinkin job no more either!
Just leave the western world!
 
centralamerica

centralamerica

Member
Many thanks for the feedback everyone. I've been busy, and getting online from here isn't always easy. I've a portable A/C (w/dehumidifier) set up and of course it's pushing all day long. Have the lights out for the 6 hottest hours of the day. It's an interim solution just for now. A friend is bringing down some blue veg tubes with ventilated hoods so I'll be feeding all the hot air through and only bringing in enough fresh air for CO2. I'll supplement CO2 later on, I'm just trying to keep everything as proven and simple as possible for now since I'm a noob, but I will be experimenting with LEDs after I get some production under my belt. I'm only concerned with rapid vegging for now since everything goes outside for flowering. ¡Estoy bendecido con una finca!
 
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