The answer to 'why is my sod yellowing' is that there are several common causes, including insufficient water, nutrient deficiencies, disease, or pest infestations. Yellowing sod can be a sign of stress or unhealthy growing conditions.
If the yellowing is localized, it may be due to a specific issue like a pest problem or fungal disease. However, if the entire lawn is turning yellow, it's likely a more widespread issue like drought or nutrient deficiency. In either case, it's important to identify and address the root cause to get your lawn back to a healthy, green state.