How to Make a Simple Rain Gauge
The average lawn needs about one-inch of moisture per week. How do you know how much water your lawn is getting from either Mother Nature or your sprinkler? Check it with a simple "rain gauge" you can make.
Take an empty tuna can or can of similar size and mark the one inch level on the inside of the can. Place one or more of these cans – space them about 15 feet apart - in an area you are going to water. Check how much water your sprinkler has applied to the area at intervals to determine how long it takes to apply one inch. You will now have a good idea of how long the sprinkler must be on to get a designated amount of moisture, and can adjust your watering methods accordingly. For example, you may want to apply a half-inch of water twice a week, so you will set the sprinkler for half the time.