Grow Box Air Exchange

[moyboy]

I am building a grow box for winter in the coming weeks and I am trying to get a picture in my mind (and on paper) of exactly what i'm doing before I build (In regards to the electrical).

Many times I have read that good air exchange in the grow box is essentail to a heathly plant, which makes sence.

My question is, Do I need to have 24 hour air flow in the box?

In winter the temps here don't drop to far below 0C on the occasion night, and only very rarely below 10C through the day, but if a fan is running at night, I will struggle to keep the temps in the box at a nice 30C

Can I just run the main air fan off the light timer which will be 12/12 or 16/8? or should it really be running 24/7?

Thanks guys and gals

 

[AlabamaJack]

Moyboy...I keep my box open about 2-3 cm most of the time...with the fan running, I figure that is good enough air exchange...the lights can keep the box at 30c with no problem...matter of fact, if the temperature in the garage is above 13C, I have to leave the door almost all the way open to keep the temp inside at or below 30C