Hello Courage,
Most dripper systems I have seen used only use one pump, and each plant site has a dripper off the same line of that pump. Can you explain why you are wanting to use a pump for each plant?
Here is an image of how drip systems are traditionally implemented (with a single pump):
https://p9m8z8i9.rocketcdn.me/wp-conten ... 809825.png
As far as your diagram it looks like you are wanting to control AC devices. I have found to be able to reliable do this you have to use a AC Snubber on each connection. Without these eventually each relay will get fail open (short open with device always powered on). I pretty much try and avoid using relays for AC power devices that have inductive loads (like fans and pumps) because of this requirement.
Here is an Amazon link to AC snubber:
Here is a link to the basic wiring of a relay:
https://hackster.imgix.net/uploads/atta ... 60&fit=max
As far as wiring your Arduino to the relay board, you should provide +5V/GND and a GPIO pin for each relay. You will also need to configure a jumper on the relay board to let it know you are providing external power source (not powering the devices directly from the Arduino). I would need specific relay module part number to give more details on how to do this.
Let me know if you need other questions on this.
Nick
) and if I could get any feedback on whether this is safe and will work I would be grateful 