yellowing leaves durring flowering???

i started 3 plants on 4-1 two from clones i aquired from buddys and one seed all were started in oasis cubes and then i moved them into a 80% super soil 20% perilite mixture in one gal nursery pots and then vegged at 18/6 light cycle under cfl lights and given no nutes for three and a half weeks then they were given some 1/2 diluted plant food 24-8-16 twice
when they were 12-15 inches i changed the lights to 12/12 to flower they have been flowering for about 2 1/2 weeks and comeing along nicely {i think} since the light change the bottom fan leaves on the plant that come from seed have started turning yellow and now some of the upper fan leaves have started turning also its NOT FROM OVERWATERING i'm sure
since the flowering has started the only thing i have given them is some bloom inhancer 10-52-10 half diluted ofcorse and water any help would be great

any one got ant ideas ????????????

its ok smoke the plant is only using up its own Nitro , all plants yellow during flowering , its what u want then to do . one thing i would say is to add more perlite to ur soil mix , marijuana needs good drainage , try a 50/50 mix the next time . getting back to the yellow leaves , ur plant doesn't need as much N during flowering as it uses this to make leaves and stem ( not flowers ) it still needs sum all the same and if it can't get it from the soil its will take it from itself . in the last 2 weeks of flowering i will be using GH ripen and its has next to no N at all . u want all or fans leaves to yellow before u harvest.
ps the bottome leaves are yellowing 1st cuz the top of ur plant needs the N
I hope this helps
SH

Its 100% normal. The plant is maturing and dying.

Dont worry, it means the plant is getting ready to die, which it would do in normal outdoor natural life.

Dont cut any off though, it'll just shock the plant, let them drop off.

thanks a shit load guys i was starting to worry that info really takes a load off my mind thanks again

yeah, i noticed that on the layout you made of the yellowing leaves. Yeah what lip already said about shock.

ya i had to take a few off for pics i kinda freaked out but it's ok i'm cool now:rasta: :thumbsup: