David WE Roberts wrote:

Possibly a microbore tube watering system fed off a water butt on the
balcony which is in turn fed from the guttering?

Thanks for the suggestion.
Unfortunately, it seems to be more or less impossible to tap the gutters,
as there are no external downpipes on that side of the house.
It would be easy to fill a water-butt from the kitchen tap,
which is only a metre or so away from the balcony.

This could provide all year watering, and you would just have to top up
the water butt if there was not enough rain.

Possibly better than a system connected to the mains because there is a
limit to the amount of water you can feed to the plants whatever component
fails.

I've always assumed - and hoped -
that if the Hozelock watering system fails,
eg because the batteries run out, it will fail by stopping completely.
But it's never failed yet, so I can't be sure ...

I assume you do not expect much rain whilst you are not there to tend to
the plants.

Actually, there is quite a lot of rain in the summer;
it comes down in brief but very heavy storms.
I was surprised to find that the annual rainfall in this part of Tuscany
is actually higher than in Ireland, where it always seems to be raining,
but in the form of drizzle.

--
Timothy Murphy
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College Dublin