Sensi skunk fem

So proper calculation!! It’s exactly 5 weeks today since germination! Been getting cold temperatures during lights out period!! So just introduced a oil heater.. when lights are out now I’m keeping a desk fan running all the time with the carbon filter fan also! Oil heater comes on when lights go out but is only reaching a temperature of 21 degrees which is better than 14-15 that I had been getting without the heater! Still unsure weather I should be putting into flowering stage yet but that’s what I’ve decided to do! Getting bigger leafs still and unsure if to trim? One of my stems did snap as maybe a little to hard on the lst! It’s made the perfect clone tho! So done some research into clonex??? Another topic that’s tricking my brain!! Introduced more light into my grow tent also which is a fan operating 600w led grow light! Not sure if the light I already have and a led one will make a difference as there not the same?? But still they look healthy??