Shed Grow

Yo I put up a wall in me shed and I am growing behind it.
I have an exhaust fan sucking air out but I have not been able to find small ducting fan to bring air in or even where to put it.

I was wondering if the air leaving the room that fresh air will automatically come in through holes?

Or if I create CO2 will that be good enough and I don't need a fan bringing in fresh air?

wish i can help but im waiting to get the same answer you are

Any air you remove, will be replaced or cause a negative pressure. You really should have twice the area of passive intake as powered exhaust. CO2 you commonly seal the room for...

I'm also growing in my shed. I have an exhaust fan pulling air across my light and out the wall. The door doesn't seal up completely so fresh air gets sucked into the shed from negative pressure. I run a home made CO2 system, but the saturation probably isn't that great. I plan on getting a tank and timer to cut the oscillating fan when the co2 is on.