Did the problem child get a little light stressed at one time?
It
Mite of been heat stressed early on,one day i was at work durning the heatwave here and when I got home it was 100 degrees in the tent ,maybe that was the start of its yellowing, then the water ppm was only 41ppm I don’t know if that had anything to do with it,my friend told me that probably the reason for the yellow leafs he told me to use cal mag and bring the ppm up to 160,so I’ve been doing that the last 2 watering ..it’s not all the leafs
maybe it’s not getting enough nutes and it’s hungry
I’ve been using 3 teaspoons of big bloom and 3 teaspoons of big grow to a gallon of water,
maybe i
Need to up the nutes,looks like it’s almost ready to harvest in a few weeks buds are tight