My smart apartment balcony is a harsh environment for plants. The Canberra sun can dry out plants quickly. One way around this is to use a self watering pot. These have a water reservoir in the bottom.
The pots are usually made of plastic and do not look as good as more natural materials. So I fitted the self watering pots into glazed ceramic ones. The air gap between the ceramic and plastic pots provides some insulation, reducing the heat in summer.
One plastic pot did not fit, so I cut the top off with a small saw. The pot then fitted, but did not quite come up to the top of the ceramic pot and there was a gap between the two. So cut a piece out of the off-cut top of the plastic pot to make an adjustable sleeve. This I inserted into the top of the pot to cover the gap to the ceramic one. The springy plastic held it firmly in place until the soil was added to cover it.
Keep in mind that some plants do not benefit from the constant water supplied from the pot and may need to be left dry some times. Also the water could harbor mosquitoes other pests in some areas.