Yellow leaves and curled down. Update:Week6 flower

@Grower_Tom if it'd be lockout then there'd be signs of Ca,Mg,K lock also i'd progress from top to bottom not other way Mo deficiency is also highly unlikely but not excluded K deficiency ? pfff xDD NOPE there is no signs

You don’t have a diary so I’ll go out on a limb and say you’re using liquid nutes and have salt build up and nutrient lockout. Judging by your other grows I don’t think you’d starve this one, that’s why I say lockout.

looks like n-deficiency and some senescence / fall colors. As far as the droop, either poor watering habits or maybe a pest chewing on roots? Something is off in rootzone, i'd assume.

That is a natural Autumn fading xDDD seriously now, this is clearly N,P starvation due to underfeeding i see a Co2 bag so u definately 'd've increase ur feeding

No diary, thats already a challenge to give right path. From look, its either cold temps ( natural fade or lack of molybdenum ( very possible )), plus lack of potassium and maybe ph drift ( from look of plant or leaf position ).

https://420life.com/wp-content/uploads/2021/10/Marijuana-Leaf-Deficiency-Chart-scaled.jpg looks like some N issues on firs glance. but also some Senescence "natural fading due to age or low temps" What is your grow room sitting at day temps vs night temps? Hard to fully tell with no diary and no idea what they been fed. Of your active diaries they don't seem to match whats in them. or the age. Biosbuzz is the nutrient lineup there and if its the same here maybe it needs a bit more runoff to flush out the buildup/leftovers. Your night temps at 16c should be ok. but lower is not ideal. want temps to be 18-28c higher is ok but not over 35 ideally. I have not used that lineup "biosbuzz" myself, but heard nice things about it. Make sure your referencing their feeding chart and not over feeding it. I know it does not like PH below 6.2 according to its feeding sheets.