Lance Walheim, the author of Lawn Care for Dummies, answers the age-old question: How low do you mow? How often and how short you mow your lawn determines how well it resists weeds, heat and drought. Each type of grass has an ideal mowing range: Cut it too low and your lawn will be shallow-rooted and susceptible to sunburn and drought stress. Leave it too high or don't mow it often enough, and your lawn will thin out and possibly be invaded by weeds.

Adjusting the Height on a Rotary Mower
Set the mower on a level surface and, making sure it's turned off, disconnect the sparkplugs and drain the gas. Lift the mower and clean out any debris on the underside. Measure the level with a tape measure and adjust the wheels to the desired height (some models allow you to adjust all four wheels at once; others, one at a time).

Tips:

• Alternate mowing directions to avoid forming ruts in your lawn.

• In hot weather, mow a bit higher (to encourage deeper roots).

• Never mow with a dull blade. You can easily remove and sharpen the blade, or you can replace it fairly inexpensively.
  
• Mow the lawn when it is about a third higher than the recommended mowing height.
  
• Leave grass clippings on the lawn, unless the grass has grown very tall between mowings. The clippings will contribute organic matter and nutrients as they break down.

  For specific mowing heights for each type of grass, see Walheim's book, which is published by IDG Books Worldwide.