assembled and built a 3rd and 4th set of shelves and put terracotta 17cm pottery planters on them. balcony now has 7 X 30cm pots, and 4 shelving units with 48 X 17cm terracotta pots.
Have another 2 sets of shelving to assemble going to put them on the second balcony. though it does get very hot out there during summer as it is a small balcony. maybe putting some shadecloth over it will be a good idea. something to think about i guess.