Mike Halmarack wrote

As I may be going to live long enough to go on me
holliers after all, is there a method of watering my
balcony plants in any way similar to this?

A large plastic milk bottle full of water on my balcony floor,
with a tube from it going straight up the wall to plants on
shelves. Is it possible to apply anything like the right kind
of pressure without recourse to electricity and pumps?

Makes more sense to use water solenoid and a timer.
Have the solenoid on the tap so that any failure is
just dead plants and not a flood.