First grow room, looking for some advice on venting for a 400 w

LouieBong

LouieBong

Member
I have a little attic room off a bedroom in my house I want to grow in and want to run a 400 w HPS/MH light but don't really have anywhere to vent the air to and I am looking for advice or if the room is big enough to not vent it anywhere. The room has slanted walls to a point but it is 8 ft long 7 ft wide and 6 1/2 feet high at its highest. I think I might have to make a tent of some kind in there to help the get the most light to my plants which I am thinking about 5 plants for the first grow. I don't really have anywhere to vent the air to but can open the door to the room that is in one of my bedrooms when it gets to hot. Just wondering if the 400 will get to hot in the room with only fans circulating air in there and if I should go smaller or if anyone has advice on anything for the room at all. included some pics

Any help or tips would be awesome. Or just some knowledge on how hot the 400 will get in there at all would be great.
 
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Phyzix

Guest
LouieBong said:
I have a little attic room off a bedroom in my house I want to grow in and want to run a 400 w HPS/MH light but don't really have anywhere to vent the air to and I am looking for advice or if the room is big enough to not vent it anywhere. The room has slanted walls to a point but it is 8 ft long 7 ft wide and 6 1/2 feet high at its highest. I think I might have to make a tent of some kind in there to help the get the most light to my plants which I am thinking about 5 plants for the first grow. I don't really have anywhere to vent the air to but can open the door to the room that is in one of my bedrooms when it gets to hot. Just wondering if the 400 will get to hot in the room with only fans circulating air in there and if I should go smaller or if anyone has advice on anything for the room at all. included some pics

Any help or tips would be awesome. Or just some knowledge on how hot the 400 will get in there at all would be great.
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Small AC unit + CO2 would probably take care of the heat from the 400W assuming the ambient room temperature doesn't get too high in Summer. Looks like there is a window in the picture, vent out that?
 
LouieBong

LouieBong

Member
Phyzix said:
Small AC unit + CO2 would probably take care of the heat from the 400W assuming the ambient room temperature doesn't get too high in Summer. Looks like there is a window in the picture, vent out that?
Click to expand...

The room is actually pretty cold right now since it is still winter but it will be getting hot out in the next few months and thats what I am worried about. I have a window AC that I will have in the room connected to that room and could open the door during lights on for it at times. That is a window but I am very worried about venting out that cause it is right next to the neighbors house and am trying to be really discreet. I am not looking for a huge setup but want to get a good light for good yield, just wondering if maybe cause of the venting problem if I should go down to a 250 hps or even a 150 instead of the 400?
 
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Phyzix

Guest
LouieBong said:
The room is actually pretty cold right now since it is still winter but it will be getting hot out in the next few months and thats what I am worried about. I have a window AC that I will have in the room connected to that room and could open the door during lights on for it at times. That is a window but I am very worried about venting out that cause it is right next to the neighbors house and am trying to be really discreet. I am not looking for a huge setup but want to get a good light for good yield, just wondering if maybe cause of the venting problem if I should go down to a 250 hps or even a 150 instead of the 400?
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Well I'm no expert but I can give you a few pieces of advice:

1. I wouldn't recommend going below 400W, that seems to be the staple size of small growers on this forum, a 150/250 wouldn't penetrate as deep or support as many plants.
2. You should take a look at closet HPS grow threads - they have the same heat in less space and probably lots of ideas for ventilation
3. If heat remains an issue and you don't want to invest in an AC unit or similar cooling method, CFLs or a T5 setup might be good for you. Less bud and less dense, but significantly less heat issues
4. Consider adding CO2 if you wont be getting air from outside regularly
5. Certain varieties of marijuana can flourish in a hotter environment than others, unfortunately they aren't always the highest quality strains. I imagine some kush varieties from the middle east would be able to handle some heat
6. Heat will slow growth and may kill plants

Hopefully someone more knowledgeable than myself will come along and help you out ;-)
 
LouieBong

LouieBong

Member
Phyzix said:
Well I'm no expert but I can give you a few pieces of advice:

1. I wouldn't recommend going below 400W, that seems to be the staple size of small growers on this forum, a 150/250 wouldn't penetrate as deep or support as many plants.
2. You should take a look at closet HPS grow threads - they have the same heat in less space and probably lots of ideas for ventilation
3. If heat remains an issue and you don't want to invest in an AC unit or similar cooling method, CFLs or a T5 setup might be good for you. Less bud and less dense, but significantly less heat issues
4. Consider adding CO2 if you wont be getting air from outside regularly
5. Certain varieties of marijuana can flourish in a hotter environment than others, unfortunately they aren't always the highest quality strains. I imagine some kush varieties from the middle east would be able to handle some heat
6. Heat will slow growth and may kill plants

Hopefully someone more knowledgeable than myself will come along and help you out ;-)
Click to expand...
Thanks,
You think a 250 or 150 would be enough for like 3 to 5 plants only? and if I used a smaller HPS like those for flowering I could go with a CFL for vegging and I wouldnt have to worry about heat during that time right?
 
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Phyzix

Guest
LouieBong said:
Thanks,
You think a 250 or 150 would be enough for like 3 to 5 plants only? and if I used a smaller HPS like those for flowering I could go with a CFL for vegging and I wouldnt have to worry about heat during that time right?
Click to expand...
That is very dependent on the strains you're growing, the hood on the light(s), the reflexivity of your walls (if you put some up), how far the bulb is from the plant etc...

150W will not be enough light for 3-5 adult plants, and 250W will probably be enough to flower if they are small but isn't ideal. 400W for 3-5 would be pretty ideal for good bud.
 
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