ok guys, my plant is in veg stage, and has just showed its sex(female) but anyway, its about 18 inches tall but it hasnt showed much growth from the nodes...like i mean i have leaves coming off the main stem but they arent branching off, and i am gettin some yellowing on the lower leaves. Ph is around 6.4-6.6. they are under cool blue flouro, 16-8. temp stays around 74 degrees. they are in just a walmart expert soil. and i have been using a miracle grow mix. can u guys help me turn it around? ne pointers?