Natural rainfall is not enough for two reasons: it doesn’t ensure an adequate amount and is isn’t dis-tributed evenly enough. This is particularly true when the lawn has just been fertilized.

A good rule of thumb is that a lawn requires an inch of water per week. A rain gauge is the easiest way to determine how much water each part of your lawn gets. This doesn’t mean that you merely put one seventh of an inch per day. The watering should soak in to a depth of five or six inches. Short, frequent waterings can cause more an-nual weeds, shallow grass roots and more chance of disease due to constant moisture. Too much water-ing will replace oxygen in the soil; the grass will die.

Factors to Consider

Shade – More water is required under trees since they take a lot of moisture out of the soil.
Soil Type & Condition - One inch of water will penetrate 12 inches into sandy soil. The same amount will soak in six to 10 inches in loam and only four to five inches in clay. You will need to adjust your water accordingly. Compacted soil will be more likely to allow water to run off and requires core aeration to remedy.
Slopes – A slope allows water to run off rather than soak in. It also means that there is more evapora-tion due to exposure to the sun if facing south or west. Weather – How often and how much has it been raining? Again, a rain gauge is helpful.