Lets start with filling out the basic troubleshooting form. I have attached it below. Fill it out the best you can.

Could be a minor problem or even nothing, my lowest leaves died on the plants I have about the time you are at.

You should be using nutes that are designed for flowering and you should be using them sparingly (low end of recommended dose or preferably less)

H=Answer if you grow hydro or aero
C=Answer if you grow coco
S=Answer if you grow traditional soil
L=Answer if you grow soilless other than coco (Promix, Hyponex, SunshineMix)
R=Answer if you grow in RockWool
T=Answer if you grow in HydroTon
D=Answer if you run any type of automatic drip system, including into soil or soilless
E= EVERYONE needs to answer lol!


E-indoor or outdoor
E-soil, soilless, coco, aero, or hydroponic
E-specific medium
CSL-Soil type/brand
HCL-Hydro/aero/soilless system type
SCL-Anything you have added to the soil
SCLR-Soil or slab runoff pH
E-Water source
E-Source water pH
HRT-Source water EC (if hydro)
E-Age of plant
E-Type of fertilizer
E-Rate of application (if hydro, this is your PPM number, preferably after each component is added)
E-Lighting source and distance from plant
E-Air temperature (both day and night if you are running a dark period)
HD-Reservoir temperature
E-Air % Relative humidity
E-Lighting schedule
E-Type of ventilation your room has
TR-Did you pre-soak your media in pH corrected solution?