Each one got a single 2-gph emitter that I mounted on a plastic stake and stuck into the pot so that the emitter stood an inch or two above soil level to reduce the chance of clogging. This left me with lots of room to play with the amount of water delivered to the other containers. The thirstiest plants got adjustable emitters capable of dousing their pots with up to 10 gallons per hour. Use a hole-punch or a nail to perforate the system's main hose, then attach feeder tubing to water individual pots. A round emitter determines how much water will be delivered to the pot.
Emitters are available in a range of capacities.
Use T-connectors and extra tubing to either water multiple pots off one feeder tube or add extra emitters to a container. During the installation, I kept a tally of the number of gallons per hour the system would need to dispense. If that hourly total exceeds your household's hourly water-delivery capacity, the irrigation system won't work properly. You can roughly calculate how much water your household delivers by turning on the hose and measuring how much water gushes out in one minute. Multiply that amount by 60 to establish an hourly rate.