Every spring I take my lawn mower into town where my good friends at the lawn equipment shop properly tune it up and sharpen the blades. Sharp blades are important to the look and health of a lawn. Grass that is cut sharply decreases water loss and increases photosynthesis. As you'll recall from middle school, photosynthesis is the process by which green plants turn carbon dioxide and water into carbohydrates and oxygen, using light energy trapped by chlorophyll.
You'll know your machine needs a tune-up if you see white tissue sticking out of the leaf blades after you mow. A cut from a dull blade results in a nutrient deficiency that will wreak havoc with your growing lawn. Sharpen your mower blade twice a year [source: Boyd].