Royal Dwarf - Balcony Grow

Day 56: The buds become thicker and the first trichomes can be recognised. On the whole, the plant looks healthy. However, some of the leaves have strange marks, according to my research this could be the leaf miner. Perhaps I should fertilise a little more, as the lowest leaves are still turning yellow. Could this indicate a nitrogen deficiency or is this normal at this stage of the flowering phase?