WATERING FREQUENCY AND AMOUNT

You should try to give your lawn the water it needs-and no more. This conserves an important resource, saves money and helps prevent grass from becoming diseased due to too much water. How much water your lawn needs depends on the health of your lawn and soil, rainfall and on your climate. You may need only two waterings per year or as many as two per week.

The best approach to deciding when to water grass is to follow nature's pattern of rainy periods followed by dry ones. Apply enough water to penetrate to the roots of the grass all at once, let the soil almost dry out and apply water again. Grass signals that it needs water by losing its spring-when you walk across the lawn and see your footprints, your lawn probably needs to be watered.

To decide how much water to apply, you should consider several things: the depth of your grass roots, your type of soil and water's ability to penetrate it and, of course, the weather. First, check to see how deep the roots of your grass are. Add an inch to the average root depth, and this will give you a target for watering depth. It makes no sense to waste water by watering to a depth that's deeper than your lawn's root zone. Root depth depends on how much time you have taken to improve your soil and on what type of grass you are growing. Some grasses, such as tall fescues, have roots that can reach one foot deep. Others only grow to half of that, even in the best of conditions. As your grass develops deeper roots, you should adjust your watering target so that you continue to encourage roots to go deeper.

Next, determine how much water it takes to moisten soil to just beyond your root depth. A good rule of thumb is that you will need one to two inches, once or twice a week. If your soil is porous and drains quickly, you would apply one inch of water at the twice-a-week frequency. Conversely, if your soil holds water well, a good guess would be two inches once a week.

To accurately determine how long to run your sprinkler to deliver the desired amount of water, set out cans after a four-to-five day dry spell. Then run your sprinkler until you have delivered one inch of water to your lawn. Wait twenty-four hours to allow the water to penetrate the soil (12 hours if your soil is porous), and then check the depth of the moisture penetration.

If one inch of water moistens soil to a depth well beyond the root depth, try the procedure again but deliver less water. Conversely, if the root depth is not reached, try delivering more water. Keep accurate records of how long you run your sprinkler to deliver the required amounts of water, and base future waterings on what you have learned. If it rains during the week, decrease your watering by the amount of rain. If it has been hot and sunny or windy, you may need to increase your watering amount and frequency.