can't get my temp below 90F

i have a grow box 2ftx1.5ftx4ft

i have 2 20 watt cfls bars going up the sides then a 150 w HPS at the top.

I started out with 1 computer fan sucking air out of the box then various holes in the bottom and some on top for intake.

the heat was way to much so i made the bottom holes bigger and added another computer fan to suck air out and then another to blow air in. i also put a big box fan outside of the box to keep air moving inside the closet. (the grow box is in a closet. so kind of like a box inside of another box).
i also have a small fan inside the box blowing upward onto the HPS.

all this and still can't get below 90F.

i was hoping i would be ok since the 2 strains i have are supposed to be OK for outdoors as well as indoor but growth has basically stopped completely.

idk what else to do, i have a total of 5 fans going in there and i still can't get it right. the A/C is set on 68F but i suppose those lights are just too hot.

i just unplugged the 2 cfl lights so hopefully that makes a little difference, but idk they are just 2 20 watt 2ft lights.

the 2 strains i have planted are green poison and Jack47. they were germinated on Nov 19. they only have 4 leaves each but so far the leaves aren't yellowing or anything like that.

i just looked at the calendar and realised that they are a week and 2 days old, so that makes me feel a little better about the size. idk they were growing so fast there for a little while and now it seems like they have stopped.



so does anyone have any tricks to get the temperatures down? if i put a tick piece of plastic under the HPS would it lower the temps at all?

upload some pics.

85 degrees is fine. But if you could run CO2 90 is fine. it just takes double the water and more nutes.

would be cheeper to buy a betetr fan than run co2...waste of time in a tiny box,
loose the pc fans, they suk..pardon the pun. get a bathroom fan at least for that. how do you have a 2 foot cfl..you mean flouro tube?? cfl are only a few inches long not 2 foot

intake should be in lower wall of box. exhaust out the opposite wall near the top. the fan inside will only make more heat. keep increasing diameter of holes for intake and exhaust ,with larger fans. move more air is the key. use a small inline fan outside the box and suck that air through there. a small investment.

im not against CO2 but i have limited space inside the closet so idk where i would put a tank. i looked at bathroom fans and the ones i can afford only push around 100 cfm. my computer fans are all 80cfm. so that wouldn't help much.

and being that i have so much air flow, i don't think CO2 would really help because it would get sucked out so quickly. but i might still try it.


i think that i might cut a hole in the wall to get new cold air coming in. the prolbem is that the box heats the air, shoots it out into the closet sucks in more air heats that up and gets rid of it before the previous air can cool down, so before long its just sucking in hot air.

i checked it this morning it did drop a few degrees without the flouro tubes, not cfl srry.


the holes for the fans are all 4" in diameter and i have 3 of those 4" holes.

i tihnk i am going to try and cut a hole in the wall so air from under the house comes in cause like i said i don't think its because of a lack of air circulation i think the air being circulated is the same temperature inside the box and outside.


we will see i will keep you guys updated. thanks for the thoughts.

I grew in a similar sized space for years. Yeah, you need to get the heat out of the closet so it doesn't just re-circulate to your grow. Flexible dryer hose is cheap and works well for getting air from one place to another.

ok i get it now. your just sucking that same hot air right back in the grow erea. and you can afford up to around 500 for co2 but not a bathroom fan???? co2 in there is a waste without a real room.
if you cut a hole in your floor...wich i think isnt a good idea. you`ll be needing a good filter to keep the creepies out of the room and other diseases now to. would be easier to buy the right hose to get the spent hot air out of the room. or use it to bring in the air form a window.

well take them 2 20 watt cfls off line and see what temps u get

i didn't know co2 setups cost that much.

trust me a bathroom fan isn't going to help much at this point, it feels like you in the middle of a tornado in there right now, PLENTY of air movement.

ducting to a window or even just out of that room would solve my problem but i have a roommate and im pretty sure he wouldn't approve of me making out house look like a mad science experiment with ducting and hoses run all over the place.

i took the housing off the closet light so now there is a hole in the cieling of the closet, and i turned off the 2 20 watt lights. so far it lowered it to about 87. but i just opened that hole in the cieling a little more so im hoping that will knock off a few more degrees.

if not then i will have to make a hole in the bottom of the wall so more cold air will come in, i will just hot glue a screen onto the hole to keep critters out.

Get rid of the 150w HPS and replace it with a 250w CFL.

Bonzi Lighthouse said:

Get rid of the 150w HPS and replace it with a 250w CFL.

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*sigh* i have thought of this too. i REALLY don't wanna do that but if my holes don't work then thats what i will do.

people get pretty good yields off CFLs right?

i have removed the reflector off my light, the ceiling of my box is flat white so it should do OK.

im hoping for this to make a good bit of difference.

I will update with the results.

Haha and here I am trying to keep my temp's above 70! =D

brownbearclan said:

Haha and here I am trying to keep my temp's above 70! =D

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your probably in a big room with plenty of airflow outside of your box right?

if you have a big room, get a few used space heaters. i used to live in a basement apartment and idk if the heat ever worked down there so i basically heated the whole place with about 5 space heaters.

I have a closet grow I switched doors and put in alittle kitty door proably could do that yourself. Anyway I have 3 hps 150 watts going and sum other lights mine would b at 92 so I put in a fan blowing fresh air in and a vent into the attic works great 79 in day 70 at night would still like it colder at night in flowering. I don't know where u live but it gets cold here at night fall and everything my buddy keeps the door cracked during day and has alittle fan blowing the colder air into closet .tiny space have 1 hps 150 and keeps it at 74 in day 60 at night he is also flowering stage .that's getto but working for him his plants look alittle better than mine and I spent a xtra 260 on door and venting plus fans so I don't know. Kitty door works if u want to see my set up I can send a pic .

ya if i could keep the closet door open then i would probably be fine, but it has to be somewhat stealth so a kitty door on a closet door would look really strange, especially since i don't have a kitty.

i checked it a few minutes ago, without the reflector its about 86.

im just going to have to deal with it until january when i get more money, i will switch the light for CFL. probably try to sell the HPS.

o well its a learning experience.


i can't wait for Spring to roll around. this indoor stuff is too involved for me.

Good luck 86 isn't all that bad ..... if u sell your hps send me a msg might b interested thanks

Fresh air from an outside source (outside the room or closet). If your pushing the air out and pulling it back in(your pulling back in warm air). You wont lower it without adding a fresh air line or switching equipment.

kpac said:

Fresh air from an outside source (outside the room or closet). If your pushing the air out and pulling it back in(your pulling back in warm air). You wont lower it without adding a fresh air line or switching equipment.

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ya thats what we have been saying for the last 10 posts.

but i can't add a duct to outside the soom because i need it to stay stealthy, i thought about putting a hole in the wall but i don't want rats and mice inside this winter. but im still thinking about it.

i will probably just let it go the way it is, maybe if i am lucky i will get an ounce or so from the 2 plants. better than nothing.