Watering your lawn and plants is the most important part of a successful landscape maintenance program. Consistent watering during the summer months is the key to a green lawn and healthy plants. It doesn’t make sense to invest money in plants, flowers, and grass, and not take care of them. The following guidelines provide a complete watering guide for north metro Atlanta. The guidelines assume a typical red clay soil, which is predominant in this area.
How to Water
Portable hose sprinklers are time consuming and inefficient. Nevertheless, it beats not watering at all. The biggest problem here is the best time for watering is the early morning. Watering in the evening increases your chances for fungus, a real killer of fescue grass. Holding a hose on each plant for 20 seconds will adequately water each plant. Trees, especially larger trees, require more water.
Repetitive annual droughts are slowly killing many trees. Unfortunately, when you see your tree dying, it is generally too late to save it. Do not neglect watering your trees, as they may take many years to replace. Your yard and shrubs can be replaced much more quickly.
Automatic Lawn Irrigation
The most efficient and consistent method of watering your landscape is with an underground lawn sprinkler system. A well designed system consistently applies the right amount of water to every part of the yard at the right time of day while you are spending your time doing something more important. It saves you time by efficiently watering your lawn automatically or with the push of a button. It also saves you from running your sprinklers too long, thus not wasting water.
How Often to Water
Follow local water restriction guidelines (see when to water). To understand the basis for watering guidelines, here is a little information about water absorption into the soil. The prevailing soil type for the north metro Atlanta area is Georgia red clay. Clay is superfine particles with properties similar to glue and cement. The clay binds together and compacts with virtually no air pockets. Tilled and aerated clay quickly compacts unless organic matter is added. Water does not absorb well into clay, and plant root systems tend to be shallow. Since water does not absorb, sunlight will dry the soil quickly. Therefore, frequent watering, daily, or every other day, is required. The frequency of watering is based on evaporation. During sunny 90 degree days, it may be necessary to water every day in sunny areas. When temperatures are 72 degrees or below, water only as necessary.
Pay attention! Look at the soil in your yard. If it is very dry, then water. If your soil is wet and not drying out, water less. Waterlogged soil that does not dry out will kill plants and grass. Many books on landscaping advise watering deeply, to a depth of 6 to 7 inches, then allowing plants to dry out for several days. This method only works where plants or grass are planted in soil with a lot of organic matter added to a depth of at least 6 inches. We advise using the automated watering feature on your controller only during periods of consistent weather. At other times water automatically as needed, or by using the manual start feature on your controller when the landscape needs watering. We recommend purchasing a rain gauge to measure rainfall amounts. Rainfall amounts of 1/4 inch or less are insignificant. The sprinkler system is generally only needed from mid April through October.
How Long to Water
As a general guideline, sprinkler zones comprised of rotor sprays, a stream of water that moves back and forth, should water from 16 to 22 minutes. Sprinkler zones comprised of fixed sprays, a fixed misting spray of water, should water from 6 to12 minutes. Hot sunny areas need longer durations than shady areas. These are only general guidelines. It is your responsibility to monitor the wetness of your yard. Common sense should tell you if your yard is too wet, decrease the watering time, and if it is too dry, increase the time.
Adjusting the Amount of Water Within a Zone
Let’s say a portion of your yard is watered by one zone. Part of this yard is adequately watered, while another part receives too much or too little water. The amount of water applied by the sprinkler system can be adjusted by changing the nozzle on your sprinkler head. The Hunter PGP rotor sprays have 12 different nozzles. The least amount of water is nozzle one, which emits a fine stream of water. At the other extreme, nozzle 12 emits a large amount of water and, if necessary, can be sprayed a longer distance. The Hunter SRS fixed sprays utilize either Hunter or Rainbird spray nozzles. The Rainbird nozzles emit less water per minute, but are more susceptible to clogging due to the smaller aperture, the opening through which the water sprays. Hunter nozzles emit more water and can shoot the water a little bit further if needed. The variable arc nozzles can be closed altogether if an area is too wet.
Watering needs vary depending on sun and wind exposure and soil drainage. Areas in shade and poorly drained soils, which tend to stay wet longer, need less water. For example, a shady area on the side of the house where the air conditioner drains needs less water than the front side of the driveway out in the full sun. Therefore, a watering zone extending from the street along the side of the driveway and along the house cannot adequately water the front by the street without over watering along the side of the house. Sometimes, it is best too split a zone into two separate zones, one for the shady area and one for the sunny area. However, this is an extra cost at the time of installation. To keep the cost of your sprinkler system competitive, this option is usually not quoted in the cost of a sprinkler system.
Budget Considerations for Sprinkler Systems
If your budget allows, the best sprinkler system waters the entire yard. Also, shaded areas, or areas that tend to stay wet, should be watered separately or not at all. At a minimum, you should have your front yard watered. The front yard maximizes your house’s curb appeal and it’s resale value. Most front yards can be watered in two zones. Additional zones to water the rest of your yard may be added later.
If you live in Fulton or Cherokee County, Georgia, you should consider purchasing a separate water meter from the county to avoid sewer charges. The payback period on this investment is two to three years.