Spring Irrigation of Florida Blueberries

Avoiding Water Stress During the Fruit Development Period by JEFF WILLIAMSON, Extension specialist, Horticultural Sciences Department, IFAS, University of Florida Gainesville, and GARY ENGLAND, multi-county Extension agent, IFAS, University of Florida, Lake County   The fruit development period (bloom to harvest) is a critical period for optimum blueberry plant water status.  March, April, and May are often dry months in Florida, and while this may be beneficial for disease control and berry quality, it emphasizes the need for proper irrigation management to avoid water stress during this critical period.  Most new blueberry plantings are equipped with some type of low-volume irrigation system for routine irrigation, as well as overhead irrigation for freeze protection.  This article will discuss irrigation needs other than those for freeze protection.  Plant water requirements are relatively low during dormancy, but increase significantly with the onset of bloom and early shoot emergence.  Under Florida conditions, a rapid increase in plant water use is typically observed between February and mid-March (depending on location, cultivar, and weather patterns) as new leaf surface area begins to develop following bloom.  Plant water use continues to increase during spring as day lengths and temperatures increase, fruit continue to develop, and leaf surface area continues to increase.  The final stages of fruit development are associated with a rapid increase in berry size just prior to ripening (typically occurring in April and May, depending on location and cultivar).  This is a critical period for maintaining optimum plant water status during a period of relatively high plant water demand.  After harvest, summer pruning that removes a significant amount of the canopy leaf surface area can result in a temporary decline in plant water use, but as the summer flush develops, days continue to lengthen, and temperatures continue to increase, plant water use will increase. […]