Without truly knowing your ph, it's very hard to say as that's the number one thing (organics aside) that has to be known in order to know fully if you're looking at a deficiency or lockout instead.
With that being said, purple streaks, can be genetics, but that's in less than 10% of the strains. The other cause for purpling stems is lack of phosphorus, though generally it's the petioles that are purple, which you have as well. Lack of sulfur is the other element that would cause stems to have purple streaks and uniquely, yellow veins with green around, which some of your upper leaves show, and a 'woody' stem. To me, the plant seems to not be getting enough nitrogen and possibly potassium as well and magnesium. Can you take a pic of the plant from above looking straight down in natural light? What have you been feeding her? and how much? Source of water?