It's a really dark purple, i dont have pics for this, but it's doing it on 3 unknown strains, and one very young white widow (3weeks or so) it's only on the new growth and its at the bottom of the leaves, could see be by night temps? or a major defiency or over feeding one nutrients causing toxicity? PS this is only happening where theres some pistils she started flowering like 2 weeks ago so theres not much yet http://t1.gstatic.com/images?q=tbn:ANd9GcQSq-xfCoeItCha6lZmoWZaexbdW14yxpHDIX_tCqssPR7dZosYpg&t=1 i found a picture it looks EXACTLY like this!
Yah the leaf stems purple is fine. If your main stems are purple post pics. Do you have solid purple on the main stems? Or purple streaks going up your main stems? Also new sprouts stems are purple for a bit.
This is outdoor night temps are about 65-75 in the recent days, way hotter in the day tho can hit 100 with the humidity.