Can i grow inside a barn outside tempeture -20 to -35?

Hi guys i was woundring is it possible to grow inside the barn with fluorescent tube but outside tempeture -35?

I'd say no.
But, put a tomato or sweet pepper in the barn overnight with the fluorescent tube. If it's fine the next day....

Get a tent, or build a shed inside the barn and insulate/heat it.

Yes if you insulate the room, the problem could be that fresh air will be very cold.

I guess il stick with my closed what you guys think?

Well the temp outside doesn’t matter the temps the plant will be subject to is what matters. Can it be done? Yes. I just started mine in the attic of my shed as growing inside house isn’t an option for me.

I made a false wall on the far wall so my room is about 4’ deep and 10’ wide with about 4’ height in the middle. Walls and ceiling are all insulated and even had to insulate the floor with spare siding I had from my house.
Between the confined space and making a hidden door that is lightproof so my wife can’t find it the whole project was quite a chore but was really my only option otherwise I would not have done it.

I have a 250watt heat lamp inside a metal trash can with a computer fan blowing the heat out as my main heat source, with a space heater as a backup so far it keeps it at least 70 degrees easily. A few drawbacks are even though it is not 100% airtight I am worried fresh air might be a problem so I may need to supplement with co2, not sure yet since it’s such a small area opening the door once a day probably will be good enough.