The answer to 'aeration yellowing' is that it is a common issue that can occur after core aeration of a lawn. Yellowing or discoloration of the grass can be caused by several factors, including soil compaction, nutrient deficiencies, or improper mowing and watering practices.
Aeration helps to alleviate soil compaction and improve oxygen, water, and nutrient absorption by the grass roots. However, the process of aeration can temporarily stress the grass, leading to a yellowing appearance. This is usually a temporary condition that will resolve within a few weeks as the grass recovers and adjusts to the improved soil conditions.