I have installed a Gardena micro-drip irrigation system as well as
below ground drip irrigation line for lawn, borders and pots.

My question relates to watering rates for pots. The system for pots
has drip heads which deliver 4 litres per hour, although I tested a
couple and they seem to go up to 6 litres per hour.

I have some medium/largish pots around 40 cm square and 30 to 50 cm
high with photinia, ceanothus, bay and similar. What rate of watering
or length of time watering using the drip heads does anyone use or
recommend? Currently I have them on one hour in morning and one in
evening - but they seem to be leaking quite a lot and I wonder if this
is too much.

I understand that the answer varies according to plant species, site,
container etc, but I wonder if anyone has any broad recommendations
for this system?