Ventilation and c02 help

this is the start of my new closet grow etc etc, the lamp is just in there to throw some lighting on what ive got so far. I have a 400w MH/HPS light to install and the plants to put in, but I am worried about Ventilation and smell later on in the grow. I was wondering if anyone out there had any ideas for my closet. the first pick is just the first tray with a hydroponic system hooked up to a timer for 3 times a day for 15 mins during the "day." The second picture is the upper corner of my closet that leads to the attic. I was thinking about cutting a small hole to install a 4" exhaust fan above my plants with ducting leading to the attic. last pictures are more of the wall next to my tray and the shelf above. Any ideas for added ventilation? please help....

if you can cut a hole and run 4in. duct to your attic that would work really good IF you get a powerful 4 in fan. No cheesy comp fans or anything. A good 4in centrifugal inline fan. I'd even think about a 6in. But 4 will doit IF its a good powerful one. Everybody and their brother has heat problems with a HPS closet grow. Been there done that. PArt growroom part oven lol. But sucking hot air out from the top into the attic will work with enough CFMs. Keep in mind that whatever the CFM rating of the fan you are looking at is, that is without ducting or filters, both of which will sigificantly reduce the CFM's.
Do you plan on closing the closet door? because you will also need intake....this can be trickier when 12/12 time comes....
But yeah nice closet, vent to the attic, dont skimp on the fan....peace.

well I would start the inline fan right above my plants on the shelf, above the light with it pulling the air into the attic, I wasnt gonna close the door but run visqueen plastic on the door frame and keep the door open with maybe a small muffin fan or oscillating fan at the bottom for intake, what do you think about utilizing more space and putting another bin in there. And should I use 3 gallon buckets or jsut fill the tray I have with hydroton, and if I did that how many plants, without any crowding could I fit in such a space

bump it up pls

ACGrower said:

bump it up pls

Click to expand...

If money isn't an issue, I would for sure add another bin and set your current light on a track... I've used them and they work nice. That way you double your grow space and you don't increase your heat. I would exhaust with a 6" fan. If the exhaust has enough pull, you can just keep your closet cracked a bit and place an oscillating fan so it can move around any incoming air. Either way, make sure the exhaust fan is somewhat strong, that way fresh air is forced through the door crack anyways... As far as smell, for like 70 bucks total you can buy some liquid ONA, a 5 gal. bucket, a packet of those expanding crystal things and a fan. This idea is on one of the forums on here. You'll have a good smelling house for 70 bucks, that way you don't have to worry about a filter. Just my .02 cents. Keep us updated....

Well I will definetly have two bins, I ordered some Jock Horror and some Master Kush off of Nirvana. I still had questions about filling the bin with hydroton and putting a screen over my exit drain (to keep from flooding the shit out of my closet). I will be starting the little darlings in super starter plugs and plugging them into rockwool cubes, from there I was thinkin about filling the bin and putting the cubes right in the hydroton-filled bin. I definetly need an exhaust fan, anyone want to get rid of an exhaust fan for cheap? lol this forum needs a Selling equipment thread. And does where do places sell the little soil moist crystals for the ona liquid. walmart?

ACGrower said:

well I would start the inline fan right above my plants on the shelf, above the light with it pulling the air into the attic, I wasnt gonna close the door but run visqueen plastic on the door frame and keep the door open with maybe a small muffin fan or oscillating fan at the bottom for intake, what do you think about utilizing more space and putting another bin in there. And should I use 3 gallon buckets or jsut fill the tray I have with hydroton, and if I did that how many plants, without any crowding could I fit in such a space

Click to expand...

I think you are underestimating the heat produced by a 400HPS. A 4 in vent and "muffin fan" for intake is not going to cut it.
CLOSET(with door open) + 400W HPS = SAUNA
CLOSET(with door closed) + 400W HPS = OVEN
get the light set up in there well in advance of your plants to TEST your ventilation system. take temperature readings in different locations and at different distances from the light. The cooler (better ventilation) you have in your growspace, the closer you will be able to get your plants to the light. Look into a cool tube.

you may get some ideas from this. https://www.rollitup.org/grow-room-design-setup/167842-air-handling-4x4x8-430watt-flower.html

I am definitely underestimating the heat output, i am a newbie and this will be my first indoor grow that I pay close attention and give lots of love and attention to my plants. I just want to make sure I do things right. I could put together the little ONA bucket with soil moist crystals together, and would I want to put that under my tray while I have the exhaust fan clearing air out above my plants, with an oscillating fan in the corner of the door frame, because I will be covering the door with some type of visqueen plastic or tarp, so no light escapes. the room will be covered with mylar before the seedlings get to a week old

I just got some Ona myself. That stuff works good. I kinda let my nose tell me where to put it. I got the one gallon jug on Ona Pro and i've made up some smaller jars with holes in the lids. Ive been moving the jars around and covering/uncovering the hole with tape, trying to get the most efficient use of it. But so far it's really doing the trick. I also made a DIY carbon filter that also works really well. Matterials for that cost me 6 bucks and 20 bucks for the carbon of which I only used half. If your interested i'll tell ya how I made it.
And yeah just go for what you think would be overkill on the ventilation and it might turn out to be just enough lol.
I have a 400W HPS in a 2x4x5 tent. With a 450 CFM 6in centifugal fan sucking from the tent and blowing thru my carbon filter (lights on). I also have a 4 in. 150 CFM fan sucking out (lights off, or on when its hot) . I also have a 150 CFM intake fan going (lights on) And another one thats blows in lights off. There is also built in passive intake holes at the bottom of the tent. So i have 2 intake and 2 exhaust at my disposal and if its 70 degrees in the room, its 80-85 in the tent. Still around 12 degrees hotter in there. If my room temp were to climb to 80 (and it will this summer) it would be pushing 90 in the tent, which is a lil too hot. A/C standing by.....
So like I said....go for overkill and it MIGHT be enough lol Good luck!

found a really good site to get exhaust fans at, so I think ive solved a little bit of my problems dealing with ventilation, now I just need to worry about heat if that becomes an issue