A three-year study of water use by two species of cultivated blueberry was conducted. The experiment was
performed on two rabbiteye (Vaccinium ashei Reade) varieties, Premier and Powderblue, and one highbush (Vaccinium
corymbosum L.) variety, Sharpblue. Water was applied to the plants using a microirrigation system. Irrigations were
triggered at three soil water tension levels: 10-kPa, 15-kPa, and 20-kPa. Water use for both species was monitored using
drainage-type lysimeters and a water budget method. Grass reference crop modified coefficients for the modified Penman
equation (Burman, 1980) during the first three years of establishment were developed based on the 10-kPa treatments for
both species. Modified crop coefficients for microirrigated highbush blueberries were below 0.2 during the first two years
of plant establishment and increased to 0.35 in the third year as the plants rapidly increased in size. Coefficients for the
rabbiteye varieties were consistently higher during all three years, reaching 0.5 in the third year.