in the winter my box gets down to low 50s. light on 72. is that an ok range? or should i be concerned?
Depends on strain and "training"
Personally in the winter all my plants start off in very cold weather from seedling till end (normally) and they don't see to mind 50F-60F lights off 70F-78F lights on (Sometimes every 68F lights on)
Although if you grow the plant always in hot weather and it starts to dip down to low 50s or below, I think it would be in shock as it has never experienced that type of cold before and will try to defend itself with more trichome production for a while, then just die off if it stays that way as it has no way to protect itself.
Not to mention growth will stop completely if the temp stays that way, you'll end up losing a ton of weight because the plant will wait till lights on to do the work it should have done with lights off.