Red stems

Coming up on the 7th week of flower and the stems on a couple of the grow tips have started to turn red. Its focused mainly on two of the smaller growtips near the bottom, but there is also some red showing on the main grow tip. Any ideas? Do I need to worry at all?

I think I read somewhere that it could be a nute diffcincy(sp) but not a 100% sure. Search it.

And many strains get that as they reach maturity. I wouldn't be messing around with it too much if all else looks healthy. You are too close to harvest now and giving plants any additives at this stage may ruin the flavor, at best, and at worst kill the plant or at least greatly affect the yield of your harvest.

Some say the purple veins are a sign of magnesium defieciency but then again many strains have the purple veins in their genes (Blueberry is one of many) so it's hard for anyone to say anything without knowing more about what you have and what you're doing.

it sounds like its just reaching maturity alot of strains will yellow and red out like fall leaves before its done.