By Julie McConnell, UF/IFAS Extension Bay County
In my 8-plus years as an extension agent one of the most frequent errors I see in home landscape maintenance involves improper watering techniques. Landscape and turf irrigation systems help to establish plants and provide supplemental water when rainfall is scarce, but it is important to manage this tool properly. Many homeowners use the “set it and forget it” approach which not only wastes water and money but may also increase plant stress or decline. Improper irrigation amount or frequency can contribute to poor root growth and increase the occurrence of fungal disease of foliage and/or roots.
Watering seems like a simple task, but if you stop to think about the goals of applying water, it becomes clearer how doing it incorrectly can impact your landscape. Here are some points to ponder:
What are the initial watering needs of my “new” plants?
When new plants, sod, or seed are added to a landscape they will need consistent watering to establish a root system that can support vegetative growth. This is called the “establishment period” and usually requires more frequent irrigation than what is needed for long-term maintenance. The goal of irrigation during establishment is to support the roots of the transplanted plant in a manner that encourages rooting into the surrounding soil. This is a temporary practice and should not continue indefinitely.
Where do I want those newly established roots to grow?
As a very general guide, mature root systems for shrubs should extend 8-12 inches deep. For turfgrass, the ideal root system is 4-6 inches deep.
How do I encourage root establishment to these depths?
Studies have shown that applying one inch of water through irrigation systems to sandy soil typically delivers the water to a depth of 12 inches. Every site will differ slightly, but this is a good rule of thumb to follow. Since you want to encourage rooting depth of 8-12 inches for shrubs, your irrigation output on beds should provide that amount of water. If watering shrubs by hand, approximately one gallon of water per 3-gallon nursery container size is usually adequate.
For turfgrass, you only need the water to penetrate the top 4-6 inches of soil which translates to approximately ½ inch of water per irrigation event. A demonstration of how to calibrate your irrigation system can be seen here https://www.youtube.com/watch?v=odIN5U9IkKM
How is maintenance watering different from establishment?
If planted in the appropriate place, most established shrubs usually do not need supplemental water after establishment unless there are extreme weather conditions such as drought or excessive heat. Turfgrass on the other hand, typically needs supplemental irrigation, however, the frequency is determined by individual sites, turf type, season, and current weather conditions. Automatic irrigation systems should be adjusted throughout the year and equipped with functioning rain shutoff devices. Even with a rain shutoff device, property owners should monitor weather conditions and turn systems off when not needed.
To determine how frequently irrigation should run on turfgrass, monitor grass for signs it needs water such as color change, slight leaf folding, and footsteps in grass not bouncing back. All of these are signs that the grass needs to have ½ inch of irrigation applied. After applying this amount, allow the grass to get back to that stage of letting you know when to water before scheduling another application. Monitor throughout the year and adjust as needed. In our area you may be able to go for weeks or months with irrigation systems shut off if you pay attention to what the grass needs. Detailed guidelines for turfgrass irrigation are available in “Watering Your Florida Lawn” https://edis.ifas.ufl.edu/pdffiles/LH/LH02500.pdf.
For more information about these topics please contact our office at 850-249-8091.
An Equal Opportunity Institution. UF/IFAS Extension, University of Florida, Institute of Food and Agricultural Sciences, Nick T. Place, dean for UF/IFAS Extension. Single copies of UF/IFAS Extension publications (excluding 4-H and youth publications) are available free to Florida residents from county UF/IFAS Extension offices.
