Leaf Wetness Influences Turf Colorant Application

Abstract

Core Ideas Conditions during application can impact the visual quality of turf colorants. The response of measured colorant color parameters to pre-application irrigation was variable among products tested. Turf colorants with increased product viscosity benefit from pre-application irrigation. Turf colorants are primarily used on warm-season grasses throughout the southern United States to maintain aesthetic quality leading into and during winter dormancy. To maximize aesthetic quality, turf colorants must be applied when certain conditions are present. The objective of this field study was to evaluate the presence of leaf moisture during turf colorant application to dormant turfgrass and its effect on measured color parameters (color, intensity, and hue angle). Four turf colorants were applied to wet and dry (i.e., irrigated and non-irrigated) dormant ‘Tifsport’ hybrid bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt-Davy] and ‘El Toro’ zoysiagrass (Zoysia japonica Steud.). Color parameters were evaluated weekly for 5 consecutive weeks following turf colorant application. Average colorant color and intensity ratings were 14 and 10% higher when dormant turfgrass was irrigated prior to colorant application, respectively. Color and intensity ratings were unaffected by leaf wetness following applications of Endurant Premium and Green Turf Paint applications. However, color and intensity ratings increased by 38 and 26%, respectively, when turfgrass was irrigated prior to the application of Green Lawnger and Ultradwarf Super. Negative effects (i.e., streaking) commonly seen during application of turf colorants higher in viscosity were alleviated as a result of pre-application irrigation. Hue angles quantified from digital images were unaffected by the presence of leaf wetness during colorant application. Results from this research indicate turfgrass managers should consider wetting dormant turfgrass through a quick irrigation cycle to mitigate possible unattractive streaking that result from the use of higher-viscosity products or increased application rates.