# 400 watt Hps too Hot, need advice on fans or cooling ideas.



## bigjayzizzle (Jul 27, 2008)

i have one plant flowering under an 400 watt hps and its my first time using a hps.  the plant was doing good for a while but has stopped growing for a few days as i am seeign signs of either a nute burn or slight overwattering. the hps is a few feet above the plant and the walls are covered in mylar and i have a fan in the room but the temps are still high. should i try and get a big fan in addition to the smaller fan to keep temps down? the room sixe is approx. 3ft by 2ft in my closet.


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## The Hemp Goddess (Jul 27, 2008)

You need cool air going into the closet and hot air going out to cool it.  Some people run their lights at night during the summer to help with the heat thing.  What are the temps getting to?  Is the closet completely light tight during the dark time?


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## GMCORP (Jul 27, 2008)

Your room is about the same size as mine.  I have a 5 inch 120v electric fan that keeps it nice and breezy in there....


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## 4u2sm0ke (Jul 27, 2008)

as Hemp God has stated....fresh air in (low)  and hot air out(high)..

what kind of exhaust are you useing?....Im afraid a fan blowing on them is not enough..JMO...Good luck


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## ChatNoir (Jul 27, 2008)

Use a tempered glass cage and cool the cage with a separate fan, exhaust the hot hair out of the room. This will both lower the room temperature and let you place your lamp closer to your plants without actually cooking them.


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## Aurora_Indicas_Dad (Jul 27, 2008)

you either need to make a cool tube,or get a air cooled hood.keep the fan running on the tops of the plants.use some duct,and a couple duct fans and make it so ones pushing the hot air out of the closet,and make it so ones pulling the fresh air in.just be happy you only have a closet,im dealing with keeping a whole bedroom cool.either way,probably one of the hardest things to take care of when growing indoors with HID's


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## andy52 (Jul 27, 2008)

I TOO USE THE 400W hps and since i vented the reflector i can lay my hand on the lens and leave it there.my plants are about an inch away from the lens.


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## bigjayzizzle (Jul 27, 2008)

i would say that the temps get to about mid to high 90's. my plant leaves were cooked again and i have the plant in recovery now. i will try to get another fan preferably a large one soon and the room is not a complete room. it is a closet with mylar on the walls but it is not sealed so i have light leaks like crazy. i constructed the other two walls out of a carboard moving box from home depot and lined it w mylar. it made a nice mock grow room but i still had light leaks and the heat was too much when i used the make shift carboard box walls so i took them out. i cant really afford to build a proper grow room for a couple more weeks, but when i do will my 400 watt hos be too much for a cabient grow? office depot has some nice tall two door cabinets that i could modify and could line with mylar, mount the hps and cut holes for vents and run d?ucts for pumping air in and out. what do u guys think? is this a good idea?


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## Albrecht (Jul 28, 2008)

I'd doing a small closet grow of about that same size though with a 600 Watt HPS lamp, and had some major temp problems, and I just decided to bite the bullet and buy a small window AC unit.  A 6500 BTU unit for $139 from Home Depot.  Of course, the back of the AC unit pumps out hot air, so I had to cut a hole in the wall to vent out the exhaust, but temps are now under control, so for me at least it was worth the money.


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## wanting_in_Orl. (Jul 28, 2008)

marijuana is a plant that likes its temps in the cooler of warm spectrum like mid 70's ive seen hotter but also hotter temps can cause your plants to become dwarfs and you dont want that. buy like a squirl cage fan because it is used to pull air out of an area which would be best for you if its to warm


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## 4u2sm0ke (Jul 28, 2008)

Hey my friend..I would like to know what you have for exhaust?..so far i have not read you having any..other then fan..thanks, just tryN  to help..we want those no hoter then 85...but feel with propper ventilation you could run 74--80..


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## statepay (Jul 28, 2008)

my advice is this . first your light should be about a foot above not a couple . secondly temp is key . try somehow to get an ac unit . fans just move hot air around .


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## bigjayzizzle (Jul 29, 2008)

ok an ac unit sounds like the way to go... do they use a lot more energy? that and an 400 hps could drive my electricity up... i have no exhaust or anything of the sort as of now but as soon as i get some money i will see what i can whip up. all the info is great guys!!!!


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## papabeach1 (Jul 29, 2008)

if your temp is over 90, then you are not ready to grow it..  you must have temp controlled.. use fans, and a/c   or stop grow, and buy a oz that can save your money..  we got 600 watt hps, its HOT as hell  we has to use vent box to be attached to the ac, use duct hose to the duct fan then to the indoor roon and the light have other duct hose to the other duct fan to exhaust (exit)
if you know any way to keep it 70 to 89 degree than use the a/c we would like to know too.. our power average is 220 a month,  its not really that bad we has 2 a/c running too. one is window a/c and other one is a/c center


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## andy52 (Jul 29, 2008)

for next summer i plan on having a portable a/c unit just for the hot days.i have no problem with heat from my light.i have it ducted,drawing thru filter,then reflector,then out the top.does very well for that.but when its high temps outside,it gets hot in an enclosed unit .hope this helped some.


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