Even during heavy rainfall this spring, I’ve seen irrigation systems going full blast.
Imagine you’re at a restaurant and the waitress/waiter keeps adding water to your already full glass. The extra water spills over onto the table and eventually runs onto the floor. But every ten minutes the waitress/waiter pours more water in the already full glass. What would you think? What would be your response?
The logical thing to do is to add water in the glass on an as needed basis. The same is true for our lawns and landscapes. We should irrigate when there is a need for water.
An irrigation system is a tool to supplement rainfall, not to water in addition to rainfall.
It has been state law in Florida since 1991 for every irrigation system to have a rain sensor device installed to prevent an irrigation system from coming on while it’s raining or when adequate rainfall has occurred. The original Florida Statutes Chapter 373 read, “Any person who purchases and installs an automatic lawn sprinkler system after May 1, 1991, shall install a rain sensor device or switch which will override the irrigation cycle of the sprinkler system when adequate rainfall has occurred.” Rain shutoff devices are readily available, inexpensive and easily installed.
To avoid over-watering, let your lawn tell you when to water. Your lawn’s telling you it needs water when you see dull, bluish-gray areas in the lawn, footprints remain in the grass long after being made and leaf blades are folded in half. When thirty to fifty percent of your lawn shows these signs, it should receive about ½ to ¾ inch of water. Early morning hours is the most efficient time to apply the water. Don’t water again until the water need signs are visible. The best time to observe these signs of water need is during the evening when the grass is not in full sun.
To determine how long it takes to apply ½ to ¾ inch of water, place coffee or tuna fish cans in the irrigated area and see how long it takes to fill them to the desired depth.
By watering this way, your lawn will develop a deep, strong root system that will better withstand drought and heat and you’ll minimize root diseases as well.
Once you’ve developed a deep root system, your lawn will do perfectly well on two to three waterings per week during hot summer months and once every ten to fourteen days in winter. When we receive adequate rainfall, no irrigation will be needed.
Learn more about Florida lawns by visiting http://hort.ifas.ufl.edu/yourfloridalawn, a UF/IFAS Extension website.