well purple stems could be due to low temps or poor oxygen or air circualtion choking the plant if u will or it could be based on the strain if ur growing blueberry or purp than yea it wouldnt be rare to see that color stem..duh lol
o alright. because i copped some purple not sure what kind but there was a seed in there. i was so suprised. and that is the seed that im gorwin with the purple.. i hope thats it.