Morning is the best time to water most lawns. Before 10 a.m. is best because rising heat late in the day tends to steal a lot of water by evaporation. There is another good thing about early morning watering – the grass leaves have a change to dry off quickly. Evening or night time watering leaves the grass wet and under cool conditions can increase the chance of your lawn developing a disease.
Most other plants benefit from early morning watering too. Scale or burn damage can result from hot sunlight hitting water droplets left on the leaves. They act just like little magnifying glasses. Early or late, give your lawn a good deep soaking, not a light sprinkling. Light watering is actually least effective and can even be harmful to your plants. The water does not penetrate the soil deeply enough to encourage plant roots to grow firm and solid. Your lawn will be less drought-resistant in summer and more prone to winterkill later.
A healthy lawn only needs about 1 inch of water a week, even during the hot summer months. You can easily measure how much water you’re using. Put some small empty containers (e.g., empty soup cans) around your lawn before you start watering. Time how long it takes to fill a container with 1 inch of water. That is how long you should water your lawn each week. It will also help identify areas that are getting too much or too little water.
This 1-inch of water is a guideline; you should adjust your weekly watering by the amount of rain your lawn receives.
If your lawn is on a slope, slow the flow rate of the water so the lawn can absorb it and not just let it run off.
A simple test is to step on a patch of lawn briefly and see if the grass blades tend to spring back up (no watering necessary) or tend to stay flat (time to water). Water only when your lawn needs it.
What Type of Sprinkler Should I Use?
Use sprinkler heads that deliver large droplets of water low to the ground. Oscillating sprays and sprinklers that throw water high into the air provide poor distribution and a high percentage of evaporation.