The answer to 'why is my irrigation system dying plants' is that your irrigation system may have issues that are causing it to over-water or under-water your plants. Common causes include broken or clogged sprinkler heads, leaks in the pipes, improper programming of the irrigation controller, or a problem with the water pressure or flow rate.
Symptoms of an irrigation system problem can include wilting, yellowing, or browning of leaves, as well as stunted growth or plant death. To troubleshoot, check for visible signs of damage, test the system's water pressure and flow, and review the controller programming. Many minor issues can be fixed with DIY repairs, but more complex problems may require a professional irrigation technician to diagnose and repair the system.