a little help

[rodambluc]

whats wrong with my leafs they're turning from green to yellow and the tips are starting to turn purple they're in the third week of flower.

 

[Love1Fear]

that sounds like like u have more then just one culprit.
U must give more description for help on this!
Hydro/soil
temp/humidity
ph meter: are u using one
water type tap reverse osmosis
ect.
"PICS say a thousand words"

 

[diesel farmer]

read this
How to Ask for Grow Support