When the lawn you work diligently to create contains dandelions, often removing the dandelions becomes a priority. Proceed carefully to kill dandelions in grass to avoid damaging the surrounding turf. Because dandelions are a broadleaf weed, there are herbicides that will target only the dandelions and leave the grass unharmed. Ensure you select an herbicide that is broadleaf selective and apply it to these fuzzy yellow weeds to kill dandelions but not grass.
Select a sunny, calm day with outdoor temperatures between 60 and 80 degrees F. Apply the herbicide on a day when rain is not forecast for two days following the application. According to the University of Minnesota Extension website, applying the herbicide in either mid-spring or early autumn will produce the most effective results. You may need to reapply the herbicide once per month to keep control over dandelions.
Spray the herbicide directly over the dandelion plant, thoroughly saturating the foliage, stems and blossoms.
Repeat the herbicide application if the dandelions still appear healthy in the grass one month later.