if you could take a picture of your setup it would probably be alot easier to advise you, pics focused on the tip of the flower dont show me much, and aluminum foil to reflect light toward the roots??? where did u read/hear to do that, not sure what positive affects that could have..
and bud on ur plants is only mildly relevant and means its a girl, ive been looking at bud on my sativa for the past 8 weeks and its still not done and may not ever get to finish as i put it outside to flower in early august, it has survived 1 frost with no ill effects, its not even in the ground, its in a 10 gal rubbermaid container both of which hurt when it comes to cold temps
after about the 6th week of flowering mine really started to swell, vertical growth has pretty much ceased and shes just gaining weight now, if u have a scope check the trichomes, some of the OG's on here say they can go strictly based on the hairs but i myself am not quite so savvy yet
im still confused on exactly how ur grow looks, do you have 1,2,4...how many plants, in a SINGLE container? why would u do this, u dont put 5 dogs in the same doghouse, they need space to be themselves
and if its at all possibly, wrapping the roots (container) with a blanket to insulate them will allow them to take colder temps yet and covering with something like a trashbag can keep the frost at bay (unless you are guerilla style then thats probably not possible)
and as for miracle grow, that's somewhat frowned upon by most in the cannaculture, there are some bloom boosters but u dont wanna add any nutes in the last few weeks prior to harvest as some say their taste comes through in the smoke, some blackstrap molasses will aid in the microbial activity in the soil but if you have 5 plants in the same pot then the soil microbes are the are prob one of the last things u should be concerned with