I'm pretty sure my whole garage was a grow setup from a prior owner. Blacked out widows with heavy duty lock 
Insulated blankets to separate rooms
Hvac tape around garage doors
Multiple sets of hooks spaced evenly apart on the ceiling
Heat

Insulated blankets to separate rooms

Hvac tape around garage doors

Multiple sets of hooks spaced evenly apart on the ceiling
Heat

Plus my wife just has to park her car in the garage in the winter
I've scaled it down just a little bit
25x25 down to 4x4