yellowing lower leaves

hi all i am a new grower and all my plants are about 5in tall. they are very healthy looking except for the older growth on them. its all truned yellow and even the ends are curling and turning brown. the tops are great and really green but after the very top its just awful. even my strongest plant is doing it. HELP PLEASE!!!!!!

This is normal dude if your plants are flowering. All plants from what I kno do that, mine are. When they start to flower I hear they use most of there juice to make the buds and the lower leaves just turn yellow and die off.

if they are almost done budding your doin great. if you are just starting give them a fertilizer with lots of phosphorus in it (nPk)

What soil are you using?
Are you using any nutrients?
Do you have a pH meter? Is so, what is the pH reading?
How often do you water your plants, and how often do you use nutrients, if you are using any?