The answer to 'sod installation yellowing' is that there are several common causes, including improper soil preparation, lack of water, and pest or disease issues. Sod that is not properly established can start to yellow and die off, especially during hot, dry weather.
To prevent and address sod yellowing, make sure the soil is properly tilled and amended before laying the sod. Water the new sod deeply and consistently for the first 2-3 weeks to help it root into the soil. Monitor for pests or diseases that could be causing the yellowing, and treat accordingly. If the yellowing persists or spreads, it's best to consult a professional landscaper who can diagnose and resolve the issue.