What a beautiful balcony Grace! It sounds delightful! The shelves must be very helpful to pack more in. Lovely to hear about the plants, mystery weeds and watering tactics too.
We placed a very brightly painted but standard shape bird nesting box on our balcony and since then not much trouble with aphids – the apparently happy Great tits return each year and seem to feed aphids to their young. I also have spells of rehoming ladybird larvae to the balcony pots, when I notice lots of plant suckers. Could that be an idea?