This is another category like watering where the attitude of, "if some is good, more must be better, " can return results which are the exact opposite of the hoped for effect. Lawns definitely need fertilizer to keep them green and growing and, more. Unless you have been scrupulously avoiding chemical fertilizers, removing grass clippings or using well-maintained and properly used mulching blades, the chances are good that your lawn has accumulated some thatch. This can be removed periodically with a.