While the east coast of Florida has been getting rain on a regular basis, much of the west coast has been lucky to get even an occasional shower. While visiting golf courses on the east coast, including some in the process of growing-in newly planted grass, there was very little talk of drought or lack of water. This differs dramatically from the west coast which, aside from a hurricane and a couple of other strong systems, has received very little rain for months. Southwest Florida, from the Tampa Bay area to Fort Myers, had their driest summer in 26 years.
This brings me back to the update “How Dry I Am, How Wet I'll Be!” that I wrote about Florida’s typically dry winters and tropical, wet summers. A week after that April update, the Fort Lauderdale area got 30 inches of rain and the water works haven’t let up since, with over 96 inches of rain so far in 2023. Steady rains can lower soil sodium to negligible levels and reduce bicarbonates in the soil, lessening their impact on soil pH and turfgrass quality. This is why you see such a positive turfgrass response after a good rainfall, particularly after you have been relying on irrigation water for an extended period of time.
Unfortunately, the west coast of Florida has had to rely heavily on irrigation water with significant levels of sodium and bicarbonates due to the lack of rain. Maintaining soil moisture around field capacity and using the leaching requirement when scheduling irrigation to leach sodium through the rootzone will usually be sufficient to manage warm-season turfgrasses in sandy soils. Some courses are applying calcium and/or potassium due to their propensity to hold more tightly on exchange sites in an attempt to further reduce soil sodium levels. Others are injecting acids into their irrigation system to neutralize bicarbonates and lower pH, which can increase the availability of iron and manganese and improve turfgrass quality.
With the well-drained sandy soils typically found in Florida, and significant levels of calcium in most irrigation sources, adjusting the acidity of irrigation water below a pH of 7.0 will limit bicarbonate accumulation and can be used in conjunction with the leaching requirement. When irrigating between periods of intermittent rain, a pH between 6.5 and 7.0 is typically acceptable. In times of drought, an occasional reduction to around 5.5 can help spark up the grass and increase its color. Be cautious when the pH of irrigation water reaches 5.5, as there can be a dramatic drop in bicarbonates and continuing acid injection beyond that point can quickly lower the pH to dangerous levels since the buffering influence of bicarbonates is essentially gone at that point. To learn more about this, check out my recent conversation on maintaining optimal soil pH with Dr. Micah Woods. In the meantime, let’s hope the busy season ahead has better weather in store for Florida.
Southeast Region Agronomists:
Chris Hartwiger, director, Agronomy – chartwiger@usga.org
Jordan Booth, Ph.D., director, USGA Course Consulting Service – jbooth@usga.org
John Rowland, Ph.D., agronomist – jrowland@usga.org
Chris Neff, agronomist – cneff@usga.org