Turf managers commonly use turf pigment and colorants for improving the appearance of sports turf areas. These are cheaper than oversowing, without the issues of removing an overseeded grass from warm-season turf. The use of pigments also occurs in fungicides for promoting plant health benefits e.g Bayer with their Stressgard® technology.

Available pigments include Vertmax®, Vertmax Duo®, Green Pig®, Sensi-Pro®, and BASF ‘s Vision Pro®. These are based on copper phthalocyanine with variations in active concentration affecting their rates of application. To better understand how these products perform, numerous studies have been carried out at North Carolina State University and more recently in Sydney, Australia by Gilba Solutions.

Vertmax turf pigment applied to kikuyu at 1L/Ha

Vertmax® Pigment applied at 1L/Ha

Why use turf pigment?

These offer a viable low-cost alternative to overseeding warm-season grasses. Drought-resistant cool-season grass varieties used for overseeding have made spring transition more difficult. Pigments also aid plant growth by increasing surface temperature. 

In the case of Vertmax® Duo, it has a secondary benefit of including plant health additives that stimulate root growth and increase stress tolerance.

Types of Product for Specific Uses.

Colorants and turf pigment are marketed in the turf industry. The two major differences are the particle size and UV stability as dyes are not UV stable. Colorants are absorbed into the material to which they are applied.

Pigments consist of extremely fine particles of ground coloring matter suspended in liquid which forms a paint film that bonds to the surface it is applied.

Colorant Influence on Turfgrass Colour.

Pigment products tend to be darker in colour, which often appears a green or blue hue (especially when applied to dormant turf). Application rates vary so much due to the amount of binder that they contain. The higher binder and less the amount of pigment content the higher the rate of application.

Innovations such as incorporating stickers have led to significantly increased longevity and rainfastness as is the case with Vertmax® with QDT (Quick Dry Technology). When applied to dormant couch, this will usually last around a month.

Vertmax turf pigment and the colour response when applied to turf

Vertmax on greens height Agrostis/Poa annua and couchgrass cut at 25mm applied at 1L/Ha

Turf pigment Development.

These were developed to improve turf appearance and also to act as a screen for UV and PAR light. When applied the pigment layer allows the transmission of a reduced intensity of PAR light and UV light is absorbed or reflected.

Vertmax Duo® is a further development that has some significant secondary benefits.

  • Increases radiation absorbance.
  • Decreased light reflectance.
  • Increased photosynthesis.
  • Increases root growth and lateral branching.
  • Increased stress tolerance.
Vertmax Duo results in an increase in lateral root branching

The LHS is the untreated control. The RHS is treated with Vertmax Duo and shows increased root branching.

Negatives

There are two main negatives.

  • They can permanently stain concrete and clothes if not used appropriately. 
  • They will not result in harder wearing turf compared to oversowing.
Differences between turf colourants.

There are several spray-on products available to keep turfgrass green. These can colour light or dormant grass and mask damage and can be used on all turf areas such as lawns, sports fields, or golf courses.

Application Conditions

The following can have an impact on the results achieved when applying these:

  • The underlying turf colour.
  • The presence of surface moisture i.e. a dew.
  • The prevailing air temperature.

If the turf is dormant i.e. couch in winter, applying these will make the turf look better. Best results are gained if you apply before dormancy as the colour of actively growing turf will enhance any colourant application.

The presence of moisture can be beneficial if the turfgrass is dormant or nearly dormant. As the turfgrass becomes more dormant, the leaf tissue becomes dryer. Adding supplemental water (irrigation) will increase leaf moisture. This helps protect the applied colourant from potential absorption into the leaf tissue, increasing the colourant’s coverage and improving colour. This especially applies to higher viscosity products. 

Many colourants do not dry or adhere very well when applied at low temperatures unless. Vertmax® overcomes this issue by incorporating a sticker. This is a consideration when applying to potentially avoid staining of shoes etc. Vertmax® also contains a spreader meaning a much more even coverage.