Intake vent question

I want fresh air intake from outside. Problem is that where I am, it can get to -30. Don't think plants would like that! How does one remedy that? Some kind of in line heater or something?

Have two rooms. One to grow in and one to exchange air with. Bring the -30 degree air into the "exchange room" and let it warm up some by mixing with indoor temps. Then just exchange the air between the two rooms.

or simpler yet just damper the intake from outside directly into the grow room and put it on a themostat.

Thanks dude! don't know which approach I'm going to take, but one of the two ideas!!!