Stems are turning brown

[paintballguy]

the stems on the branches are starting to turn brown. but the tops of my plants are starting to grow fast after i just switched the lighting to 12/12 so i dont know if its supoosed to do that or not.

 

[RooRman]

Brown huh? If you can post some picture of your problem we can help you better. Just remember to upload them to the gallery.

 

[Urdedpal]

Brown? That doesn't sound like a healthy plant. Maybe a lil more info about your grow might help but brown? Are you sure? Brown on a pot plant branch and is still a living branch?

 

[paintballguy]

lower leaves are also dieing but i assume that because they dont get alot of light. and the branches arent like dark brown just light.

 

[Urdedpal]

Lateral branching and the main stalk should be light green to a beige/tanish color with still a green hue. Lower leaves are the first to die when there is a problem, lack of light or towards the last month of flowering. Mainly its normal but it can also be the early symtoms of a problem so thats tough to tell with the amount of info you have given so far.
I am sorry, I wish I could be more helpful but there are just too many unknown variables on this side of the comp.

 

[HHGreenHand]

Any chance you are mistaking purple-red for brown? Stem purpling can be a genetic trait. I have to agree with everyone else in saying that pictures would help as well as more info on the grow.