Cold Protection of Leatherleaf Fern Using Irrigation Water

Abstract

Three water application rates, 0.38, 0.53, and 0.71 cm/h (0.15, 0.21, 0.28 in./h), were compared using an overhead irrigation system to determine whether application rates lower than those currently used in the leatherleaf fern industry could be successfully used for freeze protection. The highest application rate tested was typical of application rates currently used in leatherleaf fern industry, the middle application rate is currently being approved by the local water management district for use in critical water use areas, and the lowest application rate is currently not used in the industry. The three application rates were tested for two separate freeze events, one under strictly radiative conditions and the second under both radiative and convective conditions. The experiments were conducted on ferns enclosed in fabric shadehouses with water applied to the fabric to form an ice layer during freeze events. The results indicate that all of the application rates provided equal protection for the fern. There was some fern damage during one of the freezes with moderate wind, but the statistical analysis resulted in no significant differences in the level of protection provided by the various water application rates.