Wonder if you're watering your lawn too much or not enough? How can you tell? Today you'll learn how to be sure it's right -- both visually and by using time. Ever since Henry Parmlee invented the first lawn sprinkler back in 1872, we have wondered if we're over- or under-watering. As for how much is needed, experts say one inch a week or one-half inch twice a week (from rain or watering) is best. So how can you know when an inch of water has been delivered? First, put plastic rain gauges in key sprinkler locations. They will visually indicate when you (or Mother Nature) have provided enough water for the week. (Tip: a few drops of food coloring in the gauge make it easier to read from a distance.) Then, on a dry weather week, time how long it takes your sprinklers to deliver one inch of water onto your lawn (using your new rain gauges.) You'll then know how long it takes to properly water your lawn!