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[stash]

closet = no ventilation for a 400watt HPS. will a double fan be fine?

 

[Insane]

Simply put, no. A 400 watt HPS will generate a lot of heat, and also, plants need fresh air or C02 augmentation (properly done is very expensive) to thrive in any circumstances. How would you control the temperature?

IMO Flo-thru fresh air ventilation is the most effective/cheapest. Without fresh air or at least exchanged air of some sort, I doubt that your plants would even survive.
It would be a good idea to cut a couple holes in the closet door or something to allow for real air flow.

My last and final piece of advice would be to read a grow guide. Good luck.

 

[stash]

the best thing i have to a hole is an open hole an inch in diameter where the doorhandle belongs. also there is around a good inch of open space from the door bottom to the floor where the door is around 2 1/2 ft long. not enough is it?

 

[DillaWilla]

Stash...I am also pretty new to this but I think I can answer your question. Take a look at the link below it shows the grow box that I recently completed.

http://www.marijuanapassion.com/forum/showthread.php?t=3139

I have a 400 watt MH with an econo cool reflector (6" duct connections, and tempered glass shield), and with the ventilation you saw in my post I still have trouble keeping it under 88'F when the bedroom temp is around 75'F, tomorrow I am installing a fan blowing through the open end of the light to keep the air in the box totaly separate from the air flowing through the light. I hope this will get it to under 85'F consistently. Now I do know that a 400 watt HPS is slightly cooler that a 400 watt MH so you should have an easier time keeping it cool but you definitely need a ventilation system for that light. You should also get a temp/humidity gauge to try and keep the temps ideal, something like 78'F - 85"F with a humidity lower than 50%. Look through the rest of the growbox setup forum and you should find plenty of ideas...it is also good to ask alot of questions.

I hope this helps

 

[stash]

the ballast and components are housed in an open air ballast housing. the housing is built around copper coil ballast allowing the heat made by the ballast to dissipate fast and safely. the open air design of the high output HPS grow light keeps the components much cooler than enclosed style ballast. - this is what i got from the information on my HPS system. does this help with the over heating and less chance of needing a soild ventilation system? (using a closet with no vent holes)

 

[Hick]

the ballast and components are housed in an open air ballast housing. the housing is built around copper coil ballast allowing the heat made by the ballast to dissipate fast and safely. the open air design of the high output HPS grow light keeps the components much cooler than enclosed style ballast. - this is what i got from the information on my HPS system. does this help with the over heating and less chance of needing a soild ventilation system? (using a closet with no vent holes)

"If" I'm reading that correctly, your ballast is attatched to the light??..That alone will overheat the closet. I'm NOT the electrician that you need to talk to, but that ballast needs to be "remote". detatched and wired outside of your growroom.
BUT that still isn't going to solve your issues. Plants require a constant supply of fresh air. A good, flow through ventilation is paramount.

 

[stash]

no the ballast is remote and isnt attached to the light

 

[stash]

i did a little experiment with my fan. i stuck it in my window, intake side out and blowing side in, and duct taped a trash bag, opened on both ends, around it and put the other side in my closet under the door that has about a 1 inch high gap all across it. what do u think? haha

 

[GanjaGuru]

http://www.marijuanapassion.com/forum/showthread.php?t=3247