Lawn grass is a type of grass that is used to cover the ground in outdoor areas such as yards and parks. Two common types of lawn grass are RYE and redtop. RYE is a cool-season grass that is usually grown in northern climates and is characterized by its fine texture and dark green color. Redtop is a warm-season grass that is typically found in southern climates and is known for its deep red color and coarse texture.