The single most important thing a property owner can do for their lawn is to water it properly. Too little water is detrimental to St. Augustine grass. Without sufficient water at the right intervals, St. Augustine grass will perform very poorly. However, it is equally important to know that numerous problems are caused by over-watering.
Over-watering a lawn causes stunted roots, fungus diseases, leaching of nutrients, weed outbreaks, and higher mole cricket populations.
Watering schedules need to be adjusted for the seasons. You'll need more frequent watering in July, and considerably less in January! It's important to learn how to operate the sprinkler controller so that the watering schedules can be changed as the seasons change.
It is best to turn off the automatic sprinkler system during periods of regular rainfall. A rain sensor can be installed that will do this for you. Often in the winter months as cold fronts pass through, it rains once every week or so. This is often all the water the lawn needs.
In the summer months many lawns develop dry patches only in certain areas. The tendency may be to water more often to compensate for lack of water in these dry patches.
It is better to adjust, fix, or replace the deficient sprinkler.
Some areas don't ever receive enough water due to poor irrigation design. The solution is to fix the sprinkler system, not to water more often, which will adversely affect the rest of the lawn!
In the winter, over-watering weakens the turf, making it susceptible to cold weather damage and weed proliferation. It's also impractical as well as irresponsible for lawn care professionals to apply the high amount of herbicides that is necessary to control the excessive number of weeds caused by too much water. The effects of over-watering may not be seen right away. The lawn may look lush and green for a long time, but eventually it will suffer from root damage, weed outbreaks, and poor color.
So, what is the right way to water the lawn? In the summer it is rarely necessary to water any more than once every two days. In the winter, once a week is usually sufficient. In the spring and fall, try for a happy medium.
How long should the sprinklers run when they come on? The correct way to determine this is to set out coffee cans or cups in the lawn and see how long it takes to fill the containers with 3/4 inch to 1 inch of water. Then set the sprinklers in that zone to run for that length of time.
You can generally set the sprinkler times in the following way. Rotary sprinklers usually will take about 40 to 50 minutes to adequately water their zone. Fixed spray heads will take generally 15 to 20 minutes to produce 3/4 to 1 inch of water.
It's best to water in the morning before dawn. Watering in the morning reduces evaporation caused by the hot sun. It allows the sprinklers to cover properly because there is less wind. The wind in the afternoon will knock down the spray pattern and prevent sprinklers from reaching their full coverage area.
By watering early in the morning you also reduce the amount of time the grass blades stay wet, helping to prevent fungus diseases.
When sprinklers run in the middle of the day they often prevent landscape maintenance workers and pest control technicians from performing their work.
Proper watering of the lawn can mean the difference between having an excellent lawn year around, and having a lawn that suffers from constant problems.