How fresh must the air be for indoor grow?

I am just wondering cause I am making a setup soon
Is it obligatory to have ventilation that brings the fresh air from outside ..
or are the inside fans and tent vent sufficient?

depends on a few things. what size light? is it a cool tube? how many fans? How many tent vents and what size are they(4''or6'')? Whats the outside air temp? Im guessing its inside your house with an inside air temp 72-78ish. Best thing to do is get everthing setup, put a thermometer in the tent and do a dry run. Good luck

Circulation is most important IMO. You can use co2 in your room if you don't want to use fresh air. That's what I do, I have a fully enclosed system, no fresh air unless I open a door.

So I make a co2 setup in a room and I'll be ok..nice
thanks

not as easy as it sounds, its expensive, just get a inline fan for exhaust ,n use a passive intake,if heat temps are issue id leave my exhaust running while lights are on,if not 1x every hr would be nice

Co2 is for professional, well no, not only professional but mostly commercial growers. You should not fuck with it unless you have a lot of room to work with and you know what you are doing.

So to answer your question, if you use HIDs, you will mostly likely need to use fresh air from outside when lights are on to keep temps in check, the problem I had in the past was that when the lights were off the RH (relative humitidy) would shoot up really bad.

It has been a year now that I use LED and I use fresh air from upstairs in the house and I can have the air circulating 24-7 without RH spikes.

I strongly recommend fresh air in your grow space coming in 24-7 you will have very little chance of disease/mold

Cheers

STLbudz said:

not as easy as it sounds, its expensive, just get a inline fan for exhaust ,n use a passive intake,if heat temps are issue id leave my exhaust running while lights are on,if not 1x every hr would be nice

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I do have an inline fan,i just wondered even if have it will the room air being without windows and me opening door 2 times a day be enough for the plants
And for the co2 I will just do DIY with yeast and bubbler

Just run your exhaust fan 24/7 and you will be fine. I wouldnt waste my time with homemade co2.

mnmobbin said:

Just run your exhaust fan 24/7 and you will be fine. I wouldnt waste my time with homemade co2.

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i agree with this.. x2

E.

that fresh air hype is nonsense...
circulation helps with keeping temps down and strengthens the plants stems..

If you wanted you can make your inline blowing outward donut creates a negative pressure in the room, it'll force outside air inside threw all the cracks, windows, etc..
As far as co2 goes, it is slightly expensive I picked hup a controller unit/valve control with aa timer, and tank for like 250$ I do gotta say since then I've noticed an increase on my average yield. But I wouldn't go as far as saying its for pros in specific, you just have to know how to run the equipment.

If you want co2 and can't afford a tank & regulator just get a Exhale co2 bag at a hydro shop for around $25, they constantly produce co2 for up to 6 months, not a bad deal when you consider a tank & reg is like $200.

Controller, regulator, and a tank would be almost $400 brand new.... i wouldnt grow without co2... just my opinion..

Co2 for me is a luxury,if i can cool if not no big deal,temps/humidity,lighting,food,air movement should be your main focus along with ph, passive intake is fine nd for me i just leave the window cracked open a bit,

LOL, trust me, if this is your first grow, you will be in and out a LOT... which in turn (as long as you don't hold your breath) will supply plenty of Co2 for the plants (given you do not have a lot of plants). I went with a DIY c02 generator that has worked well for me.. or it just might be that I have been in and out over a thousand times LOL. either way it would not hurt if you have the time and materials. A pic of mine below.

please dis regard the attached thumbnail... as I converted this to the one above with the tube taped to the fan

benny blanco said:

Controller, regulator, and a tank would be almost $400 brand new.... i wouldnt grow without co2... just my opinion..

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I see co2 tanks an regulators on Craigslist for $100ea all the time, as long as there not damaged or abused they last a VERY LONG time so I feel they can be bought used, however if your grow space is in the same room you sleep and your not exhausting to an attic or other area I would highly recommend you put a co2 alarm in the room (where you sleep, not the grow space) because if for whatever reason the tank or reg malfunctions while you sleep it could very well kill you, its a colorless, odorless gas that you probably wont notice until its too late.
I completely agree with you benny blanco, I won't grow without co2 either, why not use something so simple, so (relatively) cheap and that the plants love so much, the benefits are just absolutely worth it.

LeafGnosis said:

please dis regard the attached thumbnail... as I converted this to the one above with the tube taped to the fan

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Just FYI: That's what the "Edit Post" button is for

SativaMe@420 said:

If you want co2 and can't afford a tank & regulator just get a Exhale co2 bag at a hydro shop for around $25, they constantly produce co2 for up to 6 months, not a bad deal when you consider a tank & reg is like $200.

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the part I don't understand though is at lights off it's co2 off also, it would seem at night that the exhale bag would be detrimental to the plant unless that is the bag only produces co2 at lights on and I've heard this isn't the case. also these only bring the level of co2 up in a small area by 100-200 ppm.

SativaMe@420 said:

Just FYI: That's what the "Edit Post" button is for

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sure, for words.. but attachments?, cause I tried to delete it in edit mode to no avail.

LeafGnosis said:

LOL, trust me, if this is your first grow, you will be in and out a LOT... which in turn (as long as you don't hold your breath) will supply plenty of Co2 for the plants (given you do not have a lot of plants). I went with a DIY c02 generator that has worked well for me.. or it just might be that I have been in and out over a thousand times LOL. either way it would not hurt if you have the time and materials. A pic of mine below.

View attachment 2388576

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venting the hot water tank exhaust into the grow?