What is this little white spot? First time medical grower

hey there guys. I am in 1 week to flowering and I've started to notice these little white spots on the stem of some of my leafs. their tiny and as far as I can tell they dont move...I can pick them off with my finger and have been... but what are they?

Should I be worried? I've got several dif strains and they came from clones. Predominant strains are Green Crack, Blue Dream and White Widow. Anyone with experience in these strains please let me know!

This is a flood drain system with 1K HPS and several T5's for veg.

im having the same problem

What strain? How far along are you? What method of grow?

Man, I have that too. Was wondering the same thing. At first I thought is was some kind of egg from an insect, but I've been rigorously checking for any signs of them, and I can't find any. I don't know what they are either, but if I had to take a guess, maybe excess calcium? *shrugs*