Is there any problem with recycling air if temps are in check?

[actionaaron]

I have read quite a few times over the years that the air in a grow room should not be recycled and that air should be exhausted outside the grow room and fresh air should be drawn from outside the room also.

I have gone through 3 grows now with a tent in my bedroom exhausted into the bedroom with a passive intake using the air inside the room. With a 400w hps my temps never exceed 25c on the warmest of days and rarely drop below 20c and the humidity will almost always be spot on 50% or thereabouts, so from my perspective the environment couldn't be improved much further.I keep my bedroom door open most of the time so really the new air is taken from the whole house and not just the room itself. But am I gimping myself by not using fresh air from outdoors? Any advice from our airheads is appreciated :d

[lil rasta]

yes plants absorb carbon dioxid and give out oxygen so after time the carbon dioxide would run out

[LBN]

i've always done it the same way as you, but my room is fairly big
it might be a problem in a little box room that not much bigger than your tent...

[actionaaron]

yes plants absorb carbon dioxid and give out oxygen so after time the carbon dioxide would run out

Hmm I though CO2 would spread evenly throughout the house.

[Woody J]

Hmm I though CO2 would spread evenly throughout the house.

Really?
Think about this one.
Where does CO2 come from?
Burning fossil fuels and breathing from mammals/animals are the 2 main sources inside a house.
So if the plants are in a space you rarely venture into, there will be little in the way of CO2 in there, especially if you have large plants.
The old addage, "talk to your plants, they like it" is more likely to actually be, "talk to your plants, the CO2 you exhale is what they breath".
The ppm of CO2 in the atmosphere is around 350ish if I remember correctly, if this drops, growth slows down since it is one of the component parts of photosynthesis.

I forget where I read it but if your temps are ok, you should still exchange the air at least every 4 mins to provide fresh CO2. At the same time, the CO2 around the leaves is depleated quite quickly, which is why air movement is critical.

I am not saying your plants wont grow with the method you are using, just that bringing in fresh, CO2 rich air should improve your results.
W

[Bud.]

^^^^^^ this guy is right.... Ventilation is one of the most inportant things. Get a nice big fan and filter and pull asmuch air through your room/tent as possible.... Fresh air not recycled air. Good luck

[dynodave]

id like ur cold weather pal,i used to use a 400watt drawing cold air from outside. blowin warm air out of the room,and struggle to get as low temps as u
u would benefit from CO2 enritchment.cause its so inclosed

[Novito]

Please tell me, if the temp is right, the ventillation only need for to have enough CO2?