Landscape and turf irrigation systems help establish plants and provide supplemental water when rainfall is scarce, but it is crucial to manage these tools correctly. Improper irrigation can contribute to inadequate root growth and increase fungal disease of foliage and roots.
Watering seems like a simple task, but if you think about the goals of applying water, it becomes clearer how doing it incorrectly can impact your landscape.
What are the initial watering needs of my new plants?
When new plants, sod or seeds are added to a landscape, they need water to reestablish a root system adequate to support vegetative growth. This is called the establishment period and usually requires more frequent irrigation than what is used for long-term maintenance. The goal of irrigation during establishment is to support the roots on the transplanted plant and to encourage rooting into the surrounding soil.
Where do I want those new roots to grow?
As a general guide, mature root systems for shrubs should extend 8 to 12 inches deep. For turfgrass, the ideal root system is 4 to 6 inches deep.
How do I encourage roots to these depths?
Studies have shown that applying 1 inch of water through irrigation systems to sandy soil typically delivers the water to a depth of 12 inches. Every site differs slightly, but this is a good rule of thumb.
Because you want to encourage rooting depth of 8 to 12 inches for shrubs, your irrigation output on beds should provide that amount of water. If watering shrubs by hand, approximately 1 gallon of water per 3-gallon nursery container size is usually adequate.
Water needs to penetrate 4 to 6 inches for turfgrass, so you only want to apply about ½ inch of water per irrigation event.
For details on frequency of watering for establishment, see “Establishing Shrubs in Florida Landscapes,” http://edis.ifas.ufl.edu/ep391, and “Establishing Your Florida Lawn,” http://edis.ifas.ufl.edu/lh013.
How is maintenance watering different from establishment?
If planted in the appropriate place, established shrubs usually do not need supplemental water unless extreme weather conditions occur, such as drought or excessive heat. However, turfgrass typically does need supplemental irrigation. Frequency is determined by individual sites and prevailing weather conditions.
Automatic irrigation systems should be adjusted throughout the year and be equipped with functioning rain shut-off devices. Soil moisture sensors may also help you keep tabs on your landscape’s water needs.
Learn more about soil moisture sensors at http://edis.ifas.ufl.edu/ae437.
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 the grass needs to have a half inch of water 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. Many months, irrigation systems can remain off entirely if you pay attention to what the grass needs.
For turfgrass irrigation guidelines, see “Watering Your Florida Lawn” at http://edis.ifas.ufl.edu/lh025.
For help with horticultural questions, contact your county extension office. Note that staff may be working outside offices during COVID-19. For extension information, visit ffl.ifas.ufl.edu.