What is happening to my babies? Help please

[EmzyCxxx]

Hey guys. Maybe i could get a bit of advice as im not sure what could be causing this maybe 1 of 3 things. My plants leaves (critical kush) has gone yellow from the bottom and at the top on some. Some leaves have black dots on them and some leaves have white dots on them?? I thought it was a magnesium diffiencey or maybe the PH levels are wrong (currently sat at 6) or a bug problem maybe not enough lighting or maybe too cold im not sure. I have attached photos. It is currently in flowering stage only by around a week into the flowering stage.
Any advice is much appreciated
Thank you

 

[Why Doe]

Search for the sticky "how to ask for grow advice"'copy and paste that and give us all that information. It's really needed in order to help you out.

 

[AnimaSola]

I would wait another week and trim all the bottom growth off.
Giant plant small pot, looks hungry, like its using the bottom leaves for N food. I give my plants veg nutes and calmag until they are 2 or 3 weeks into flower and done stretching.