Comparison of Color Parameters of Green Turf Colorants Applied to Bermudagrass.

Overseeding has long been a popular practice among turfgrass managers to provide green color during winter months. However, the recent introduction of green colorants has increased interest in these products as an alternative to winter overseeding. The primary objective of this field study was to evaluate the visual colorant color, intensity, and hue angle of 27 turfgrass colorants applied to dormant bermudagrass. All colorants were applied at two rates (75 mL m^-2 and 112 mL m^-2) to bermudagrass (Cynodon dactylon x C. transvaalensis) mowed to two heights (0.6 cm and 1.3 cm). Multidimensional scaling and cluster analysis were used to separate colorants into three groups based on visual colorant color, intensity, and hue angle. Group 1 colorants maintained colorant intensity the longest, but colorant color was reduced due to the appearance of bright blue (e.g., Munsell 5BG/6/6) and lime green (e.g., Munsell 7.5GY/7/10) colors. Group 2 colorants provided the darkest green (e.g., Munsell 5GY/4/4) color for the longest period while Group 3 colorants provided minimal change in color to dormant turf after initial application. Among the Group 2 colorants, Green Lawnger, Lesco Green, Ultradwarf Super, Southwest Green, Experimental 2, and Endurant provided the best color prior to needing a second application. A secondary objective was to examine colorant transfer from the turfgrass surface over time. Measurements of colorant transfer showed that Blue, Regreen, SprayMax, Green Dye Turf Colorant, Titan Green Turf, Solarogen, and Endurant have the highest propensity to disassociate from the turf foliage. Colorant transfer was also dependent on temperature during application, with transfer being at least 38% lower when applied at temperatures above 10°C compared to temperatures below 4°C.  These results provide turf managers with a number of colorant options as well as guidelines for certain environmental conditions that must be considered when applying turf colorants.