Please help me before its a waste

this is my first try at growing and my plants r doin nice, but some leaves r dying off turning brown, and light yellowish
PLEASE HELP
what fert or what should i use

i got a 1000watt hps on em and reg use mircle grow all purpose cus i dunno what to use and their already buddin some of em pistils is whiteish still PLEASE HELP

Hmm, a little more info would be helpful. But from what you are saying, it sounds like they are in the flowering stage right now. When you are in flower, the plants don't need N anymore - or hardly any. The leaves will turn that color because they are lacking N.

Don't use MG, that stuff sucks. Look for anything online, or look for a hydro store around your town. You are going to want something high in P and K. I like to use organic nutes. What kind of soil are you using?

How are your temps? What's your PH like? How long ago did you switch to 12/12?

give em straight water, check under leaves see little little tiny tiny black spots? if so bugs argh. spray with wat ever bug spray you use but remeber NEVER EVER spray the ladies when lights on or it will mean lights out for your ladies, you will burn em n then they die n u cry

Its probably the MG soil combined with too much watering. Make sure you are letting the soil get very dry before you water. MJ plants HATE wet soil, the only time you should have wet soil is right after you thoroughly water the soil, then you wait until the pot is very light and there is almost no moisture in the soil. Miracle Grow soil has time released nutrients in it from the ozmocote balls, they release fertilizer when they get wet, so everytime you water you are fertilizing, which is probably the casue of all your woes.