What causes Woody purple stems?

[Covey1024]

All of a sudden my plants stem started to turn purple and Woody.

 

[growsince79]

Could be phosphorus def. Whole plant pic might help.

 

[revfunk]

Phosphorus deficiency possibly. Also can be indicator of being root bound/drowning/suffocating

 

[swusler1954]

All of a sudden my plants stem started to turn purple and Woody.

I don’t know if you got this solved but I had the same issue. I ran it down and it was a Cal-Mag deficiency. Mostly Magnesium but they work together so you have to work it a little to figure it out.