What symptom indicates herbicide carryover in turfgrass?

Thinning grass is a key symptom that indicates herbicide carryover in turfgrass. When herbicides persist in the soil for longer than expected and come into contact with the grass roots, they can adversely affect the health of the plants. This interference can lead to stress, resulting in thinning or patchy areas where the grass fails to grow as robustly as it should.

In contrast, dark green patches are typically associated with areas of plenty of nutrients or water, and thus would not indicate herbicide damage. Blossoming flowers are not relevant in the context of turfgrass, as most turf systems are not intended to flower, and their presence could indicate a failure to manage the turf adequately. An increased growth rate may suggest that the grass is thriving, rather than suffering from residual herbicide effects. Therefore, thinning grass is a telltale sign that herbicide carryover has impacted the lawn's health.