How long is the timer set for?
Do you have a pressure regulator on the system?
What does he have in the beds as the water source?
The water leaking out the bottom of the containers, sounds like it is on for too long. Can you post a picture? You can email me one if you like.

Hopefully a simple adjustment to your timer will fix things.

I too wonder if there is a regulator (supposed to "slow" down the flow of water)?

I hope your hose doesn't have a leak. If so, those can be challenging to find and repair (often requires some digging).

It's too difficult to know exactly how much water your plants in your garden need, but seems most literature recommends running the system a couple times per week in the spring and maybe a little more often in the summer (heat and plant size). Those are just guidelines. So much depends on how much water your plants are receiving, the soil type, and the weather. Just use a little common sense and "read" your plants' needs.

Good luck.

Your system is obviously broken. The previous responses should help. But knowing your plants water needs means you need to be Einstein or wait until you see wilting, which could be fatal (to the plant) if you wait too long.

I found a system with a soil moisture sensor that prevents all that at ecosensesystems.com. I just installed the system and soon will know if is as smart as they say it is.