I'm hydro not soil but I can tell you , you need to learn way more about watering. My soil buddy says waterings should be twice the amount of the container so as to completely saturate the soil and help wash out contaminates.
By only wateing a 1/2 gallon you may think it's wet and it is on top but very dry deep down where the roots need it most it's not. fertilizing maybe the same only localized on top and not deep down.

just a thought.
LOC NAR on probation Reviewed by LOC NAR on probation on . Please help me figure this out some one tell me why she is turning yellow. 4 or 5 weeks into flower. 400w s/v on 12/12. fox farm big bloom in fox farm soil as medium in a 5 gal container. feed once a week and water about 1/2 gal every 3rd day. ph of water going in around 4 or 5, comes out high 6. room temp is 80 to 74 This is a first time for me. Do not know what strain she is. any advise is welcome. watering, feeding amount, what leaves to pinch, anything will help Rating: 5