The answer to 'why is my lawn dying plants' is that there are several common causes, including overwatering, underwatering, disease, pests, and improper mowing. Symptoms may include yellowing, wilting, or bare patches in the lawn.
To troubleshoot, first check the soil moisture - the lawn should be moist but not waterlogged. Adjust your watering schedule as needed. Look for signs of disease like fungus or insects, and treat accordingly. Make sure you're mowing at the proper height for your grass type. If the issues persist, it's best to call in a professional landscaper to diagnose and resolve the problem.