Hey I'm new grower and need a little more help trying to configure my ventilation. I really can't find a good way to say this, but I guess I cannot figure out where to find the best balance between air circulation and adding Co2. I have a 2'x4' closet and I am fermenting beyond what I feel like I would need for my grow room. I know Co2 is just one component to the air that needs to be taken into consideration so do i want to worry about getting fresh air circulating into the grow room? I feel like gases in the air diffuse quickly so if I had a ventilation it would make fermenting pointless. I hope somebody understands my issue. I'm just trying to take all factors into consideration to make the air in my grow room ideal!

Hey hows it going. Well depending on how many plants your growing you may not even want to worry about more c02. Can you open the grow room up a while everyday? Passive ventilation may be the only thing you need.

Thanks! I'll take your advice. I think I'm just trying to hard because it's my first grow and I'm incredibly excited.

I hear ya, it's very exciting! I did see a thread or two on this forum, that says somthing about the exact rate of air exchange for useing C02, you could try searching for them. But honestly, let your plants be your guide - are they growing well? Kickin ass and taking names? Then you're probably ok!

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" I grow vegetables-if anyone (including me) says otherwise they are lying."
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For your first grow i wouldn't worry about CO2... Get at small computer ventilator to exchange air in you room, that is all you need..
My first grow was also a closet grow with 150w HPS without CO2, and the buds were huge (for a 150w).
PM me for evidence

So far I only have two seedlings under florescents but I will be expanding soon. I've got a HPS 250w, built in ballast probably arriving early next week. I'm worrying about the ventilation now because when the light comes, the real grow begins! I guess I forgot to take into account temperature increases from the light. Does anyone expect that to affect my grow? If so could I remove the components to the ballast and rewire them externally outside my grow closet? I really appreciate everyones eagerness to help other people on this forum!

2'x4' closet right? Yeah the light will probably raise the temps, but yes you can put the ballast outside the room. You'll have to watch your temps the first couple of days, if it gets too high you'll have to do an active air intake.

__________________
" I grow vegetables-if anyone (including me) says otherwise they are lying."
GHS Trainwreck http://www.rollitup.org/grow-journal...rainwreck.html
GHS White Grow http://www.rollitup.org/grow-journal...hite-grow.html

Does the ballast generate a good portion of total heat of the light system making it worth converting to external? If I need to create an air intake, how do you think I should do that in my situation? I was thinking I could put a computer fan in the door knob hole if the knob was removed.

I have a pair of 400w in my grow room, and in my opinion, more of the heat is generated by the lamps themselves. However - my room is approx. 8x7x8 , so in a smaller area you might find a more noticable difference. You can always try it in there, and then rewire if it does prove too hot.
As for air - yeah you could do that, hard to offer suggestions without seeing a pic of the area. For myself, I put a 8" hole right through the floor into my dining room ceiling, so I could pull air conditioned air into the room.

__________________
" I grow vegetables-if anyone (including me) says otherwise they are lying."
GHS Trainwreck http://www.rollitup.org/grow-journal...rainwreck.html
GHS White Grow http://www.rollitup.org/grow-journal...hite-grow.html

Hello , Im also a new grower, wondering if u guys could help me.,
im from denmark, so my english isnt that good, sorry...

I just build my own growbox, mes: L:100cm h:125cm and d: 65cm in the bottom and 50cm in the top..
im jusing 2 computer fans, one for air in, and one reversed for air out.. The fans i have jused is the ones in my pic. AF 9225 pwm fans. 92x92mm, air flow 24CFM / 57.7m3/h
Is it enough to for my air out, it dont feel like much when i put a hand in front of it.
And could it work, if i'd make a homemade carbon filter and fitted it on to the fan..

Hope some one can help me.
I just seeded in soil waiting for it to germinate, but would like to be finished with the box before my baby needs to see the light