Just because you have an irrigation system doesn’t mean you’re saving water…
How often does your irrigation system come on when your grass doesn’t need any water? Have you been putting off checking the system? Perhaps you rationalize that it isn’t hurting the grass, so what’s the harm? Actually, besides the obvious answer that it is wasting water and money, too much water DOES harm your lawn. Overwatering encourages turf to grow shallow roots which cause the grass to stress if water isn’t available. And, if your system is still on during the winter months when St Augustine and other native grasses are DORMANT and need no more water than Mother Nature provides, the waste factor multiplies.
Experts point out that the basic recipe for growing healthy grass while saving water is tied to selecting the right grass for the location, having really good soil, and understanding exactly how to take care of it. That means knowing specifically how much water it really needs to thrive.
About half of the lawns in Texas are planted with St. Augustine grass, which many believe is especially “thirsty”. According to the experts at Texas A&M AgriLife Extension, however, that might be a “bad rap” since all grasses use about the same amount of water at the same rate when it is available in the soil. The ability of a turfgrass to survive if water is restricted depends on its drought tolerance and the type of soil — how deep it is, and how appropriate it is for growing the type of grass that is planted. The deeper the soil, the more likely the grass can survive even 60 days without water.
Throw out the old “inch of water a week” advice that may or may not be the formula for your lawn. Most yards can get by with less than half of the irrigation currently applied. Water moves into clay soils at a rate of about 0.09 inches per hour…not very fast. An irrigation system, on the other hand, may apply water at a rate of 0.25 to 1.5 inches per hour or more. Delivering water faster than a soil can absorb during one application results in water moving across the soil surface, running into the gutter, and down into the storm drain – and that causes another problem altogether.