Stems are turning redpurple....

5 weeks into veg.
400W HPS, 19 in. away from Canopy
Fox Farm Grow Big (2 Tsp/gal. every other watering)
Fox Farm Ocean Forest soil
Potted in 1 gal. bags
64 degrees with light on.......60 degrees w/o light.


Any ideas why some of my stems and stalks are turning red/purple?

Ive had the same thing happen a few times,some people think its a problem while others don't, just let it grow!

Yea, Everytime i grow they turn purple.

Roger Dodger. Thanks guys. They seem to be growing healthy.