Purple Stem and Branches

These plants are 25 days old from the sprouting and are in the first days of second vegetative week (according to my calculations).

As you can see in the pictures the stems have purple lines. The upper part of the branches are also purple.

They were transplanted 18 days ago and watered twice since then. A general purpose (7-6-6) nutrient solution was used in the second watering (4 days ago). I guess the soil also had some nutrients in it at the start.

According to the "problem diagnosis guide," purple stem points to sulfur deficiency, but these plants don't have any other sign of sulfur deficiency than the purple stem...

So what's going on?

Thanks.

Love to know, have a baby doin the same thing and its about the same age. +rep to someone that know

i know that it is not always a bad sign....as long as the leaves and stems are perky,she will be ok, some plants do this naturally, and some to lower temps.

No worries man. The plant looks healthy. I have a bunch of plants in veg and they're all doing the exact same thing. It's either because it gets below 70 in that room at night, or because of the light itself. Either way, I've not had any problems getting to harvest with purple stems in veg.

Yeah man, same as he said. I have a youngster that's doing the same thing. I hope the buds will be that way too. And some other babies that are staaaarting to. But they're doing fine. Good luck on your grow