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Hps in Attic Still need to ventilate?

Tool46

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Hello everyone. So since my attic is huge and i mean huge. With an HPS light setup. Would i still need a ventible hood? Or is that mainly for grow boxes? I am still going to rig a regular fan to a 4in dryer hose to vent some heat out of the attic through one of the light sealed vents? Would this be enough. Or should i still get a ventible hood, and an inline fan to vent the heat though the hood it self? any help i would appreciate. PS sorry about the long read.
 
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What size light is it?

With a 250w or 400w you might be ok, anything larger and you'll need a cool tube or a ventilated hood
 

Tool46

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I was hoping for an 600w HPS setup Cuz i always have 5 or 6 females in my flower room/ attic. Would a 400w be enough light for that many plants?
 

Exile06

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ideal is 50 watts per sq/ft and by that with a 400 u can grow 8 plants
 

GanjaGuru

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An attic makes a poor choice for a growspace.
It's not uncommon for attic temps to run 10--20 degree's hotter than outside, and that's before you add the heat from an HID.
Also attics are generally hard to ventilate, and marijuana needs lots of fresh air.
I realize that you have to make do with what ya got, but just realize you will have heat and ventilation issue's that most indoor growers don't face. You'll most likely need an A/C and lots of fans and ducting.
 

Tool46

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"An attic makes a poor choice for a growspace.
It's not uncommon for attic temps to run 10--20 degree's hotter than outside, and that's before you add the heat from an HID.
Also attics are generally hard to ventilate, and marijuana needs lots of fresh air.
I realize that you have to make do with what ya got, but just realize you will have heat and ventilation issue's that most indoor growers don't face. You'll most likely need an A/C and lots of fans and ducting. "

GG I do realize they aren't the best conditions. This is my second grow the first one was succesfull up in the attic. But was only Fluros/ cfl's. And well the weather hadn't gottent real warm yet. So a venible hood and an inline fan wouldn't be enough to keep the plant happy? I really need some help here before i go buy my light system and fan/fans. Thanxs
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Stoney Bud

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Tool46 said:
I do realize they aren't the best conditions. This is my second grow the first one was succesfull up in the attic. But was only Fluros/ cfl's. And well the weather hadn't gottent real warm yet. So a venible hood and an inline fan wouldn't be enough to keep the plant happy? I really need some help here before i go buy my light system and fan/fans.
Here's what you need to do Tool46. Figure out how many square feet of plants you want to grow. Calculate how much light you'll need to accomplish this many plants.

Put the lights up and run them for a couple of days. Measure the temperature of the grow area with the lights on at the hottest part of the day.

Add ventilation or a/c until the temperature stays below 90 degrees F.

It's that simple man. Make sure you add an appropriate amount of degrees for what your max temp gets to in your area.

If it's 80 F outside and you need one vent fan to bring it to 85 F in the attic, then if it gets to 100 F in your area, plan on either adding a/c to your area or better ventilation.

The goal is to keep the temp down below 90 degrees F. You'll have to put your lights up to see what effect they have in your EXACT situation.

Good luck to you man. Let us all know how it goes.
 

Tool46

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Thanx Everyone for the advise. I guess i will just give it a try if there a will theres a way. And well im way to far in the process to give up now.
 
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If you can grow somewhere else in your house then do so

Personally I think you'll be fine, I have 1000w of hps for my attic flowering box,

I dont know how hot the summers get in your part of the world but mine go up to about a max of 95 degrees

I have 2 powerful inline fans, 4 inch for the cooltubes the lights are in and 6inch for the grow box main exhaust. both vent directly outside

It does get a bit hot in the summer but the plants still live...
 

Tool46

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Ok Well here is what i got going. A 400w Hps with Ventible Hood, glass bottom And remote Ballast. With 4in ducts. I have one Inline fan hooked to the hood sucking the hot air directly outside. I have one more Inline fan not really sure why i needed two? but i have it if you can help. I guess that one needs to run directly from outside pulling fresh air in? right? Do i need to put fresh air into the hood as well as pull it out? or is sucking the hot air directly outside enough? Can i just mount the other inline on the floor and pull fresh air in would this be good enough? Sorry about the long read. First time hps user. Always used Fluro's/cfl's. Never need this much ventilation!
 
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You want to vent the grow area too, i couldnt make out from your pics if you hps is based in a box or in a conrner of your attic. If its the latter, you should be ok with a table fan blowing on your plants. If you have a box then you will need to vent the box as well as the light...
 

Mutt

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Hey, I'm in the middle of getting my attic grow set-up. What will help to. is run the lights (if flowering) to kick on around midnight and turn off about noon.

I found the daylight heat has fully left the attic and is cooled down and doesn't start to heat up until 2:00pm. I'm in the SE where it gets hot.
Also during July and Aug. may be wise to shut her down. (I have to for temps of 100F+) and have a veg. box with florous to store mothers.
 

Tool46

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Yeah i wish i could do that. That would fix alot of my heat problems. But unfortuneately that doesn't work with my schedule. I wouldn't be able to take care of them in the light on periods?
 

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