We often talk with folks about watering lawns and the most frequently asked questions related to watering are 1) "How often should I water my grass?" and 2) "How long should I run my sprinklers?"
How often should I water my grass?
The answer to this question is simple: Usually not more than twice per week unless you are establishing a new lawn with sod or seed. More frequent watering may be causing more problems with your lawn.
Many people we talk with say they water twice a day, every day, every other day, or at least three times per week. If you are one of these people you may be enabling your lawn's addiction to water and creating weed and disease problems. The frequent watering offenders tend to be those who have automated in-ground irrigation systems.
The problem with frequent watering is not that you are using more water than necessary (although you might be). The problem is that by watering frequently, you may be preventing your turf from reaching its full potential for heat and drought tolerance. Furthermore, you are creating a more ideal environment for fungal disease and some of the most invasive and hard-to-control weeds that we see in Raleigh, NC area lawns.
Some of the most frequently watered lawns that we see in the Raleigh, NC area have the worst problems with tough summer weeds including nutsedge, crabgrass, or spurge. Pathogenic fungi also love moisture. They develop on the blades of your grass, and the more frequently you wet your grass down the more likely you will be to eventually see a fungal disease which can kill large sections of your lawn very quickly.
In mid-summer when daytime conditions are sunny and very hot a lot of water may be lost to evaporation. In the absence of rain you may wish to water a third time during a week. However, the recommendation of Crownover Green for clients with automated irrigation systems is to set your sprinklers for twice per week in the morning, and manually run them a third time only when needed.
For how long should I run my sprinklers?
The answer to this question is not as simple because different types of sprinklers vary in the amount of water they put out in a given amount of time. There are different types of sprinkler heads that have varying rates of output and varying ranges of motion. Therefore the length of time your sprinklers should run depends on the particular sprinklers you use.
Here's how to determine how long to run your sprinklers. Put out a few soup bowls around your lawn. Then run your sprinklers to see how long it takes to fill them with the amount of water that your type of turfgrass needs. Zoysiagrass and Bermudagrass lawns should thrive on 1" of water per week through the summer, so they should receive .5" of water twice per week. Tall Fescue lawns need at least 1.5" of water per week, so they should receive .75" of water twice per week. If you have an automated in-ground irrigation system, be sure to put bowls in the various zones of the system. If you use hose-end sprinklers, put the bowls in each area as you water.
Turfgrass that is watered well twice per week and properly mowed (read about proper mowing in a previous blog article HERE) will be healthier and look better through the growing season. If you have been a frequent waterer or if you have an immature lawn, you may need to water more frequently at first and work toward twice per week.
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