help needed first time

:confused: new grower here havin some problems . I have 14 white widows .when they were in vegitation i had the temp at a constent 75 ,now they have been in 12/12 for 3 weeks but temp has droped to 70 during day and 45 at night with heater on and getting colder as it does in scotland. will a halogen heater do or will the light of it damage yeild or plant . any help be greatly recieved as first time and paranopid like a madman. :confused: :o :( :stoned: :smokin:

you cant have light on a plant a night it needs a least 12 hours of darkness a day but green lights dont affect the plant