Help me diagnose problem??? first grow

Being in its 9th week it should be close to finished, yellowing starting at the lower leaves and moving up is completely normal when the plant is close to finishing. Now i dont know what starin youre working with but the majority of your leaves still look fine. I believe if you were looking at nutrient burn you would see the problem on all the vegetation. Could possibly be lockout but youll have to test your runnoff and flush if thats the case.

Flowering plants can be very hungry for certain nutrients like phosphorus, potassium, calcium, magnesium and a little bit of sulfur. They dont need high amounts of Nitrogen in flower though. I would use that nettle juice only in veg and look for other more diverse fertilizers.

Your fertilizer is not very diverse in its contents, thats basically sugar water with some nettle in it. the NPK ratio is off and i cant find any ratios on the other elements like Ca, Mg, S and the others. There is probably a disbalance of nutrients going on here, with some kind of deficiency aswell, as plants need 14 essential elements besides N P and K.