This is my first grow and I've done a lot of mistakes. First, two plants are in the same pot: Slow growth?

I've been fighting with spider mites for weeks. About six weeks ago, I thought only two weeks left till harvest so I stopped giving any nutes. They've been only getting molasses for more than a month: Slow growth...

They were doing fine the first six weeks until the growth slowed down and that was when I first noticed the mites.

They completed 13th week of flowering...

I know.. I suck at that one...

Are there any rules like, "cut down your plants if they have been flowering for more than 13 weeks or so, cause they won't be getting any better after that period"?

I'm asking that question cause those photos were from bottom area. Top parts are another story. They look less matured compared to bottom parts.