Red streaks in stalk

[GROWxMOREx420]

Phosphate, mag., calcium deficiency will cause this. Mostly phosphate. So the book says.

From my experience this seems true. I usually get the vertical purple/red striping up the stalk during veg, then when I start flowering them and give them bloom nutes with high doses of pottasium & phosphate they go a normal color. *Shrugs.*