Building a Healthy Green By the Numbers

Testing is conducted on green constructions to determine if construction contains appropriate particle size. (Photo courtesy: Profile Products)

In our health-conscious society, we have grown accustomed to abiding by numbers. We check and monitor the numbers according to our weight, blood pressure, cholesterol, fat grams and blood sugar to gauge and determine our overall healthiness. Sure, we may feel great, but the numbers are an indicator of what will happen if we don't make adjustments in our lifestyle.

The development of a rootzone mix is similar in that its numbers give you an outlook of the potential success or failure of it or its forecasted performance. Numbers are often thrown freely around to define a United States Golf Association (USGA) mix of an 80:20 (sand:peat) or a 90:10 (sand:inorganic). Although these numbers may be valid for the sand and amendment in question, the numbers are often used as a one-size-fits-all guideline.

However, one should never assume or guess an ideal mix ratio of sand and amendment(s) for the construction of a putting green. Representative samples of the desired sand and amendment(s) should always be sent to an A2L2-accredited soil physical testing lab for a complete analysis. The lab will furnish you values or numbers that provide insight into the potential use and success of utilizing the submitted materials for the construction of a putting green.

One should note that these results also do not provide a guarantee for success. The testing methods were developed and based upon the assumption that all the steps listed in the USGA's "Recommendations For A Method of Putting Green Construction" are followed and adhered to without exception. Many greens have been constructed using the proper mix ratio of sand to amendment only to fail because of such things as poor construction methods, contamination during installation, changing of topdressing materials, improper watering regiments or lack of necessary cultural practices. Still, if one doesn't begin with a properly designed rootzone mix, the chances for success are greatly reduced and the cost for maintaining a desired putting surface will require greater inputs and a long-term financial commitment.

The 2004 revision of the USGA's "Recommendation for a Method of Putting Green Construction" provides for the optional use of porous inorganic soil amendments such as calcined diatomites, zeolites and porous ceramics in the development of the rootzone mix, provided the particle size and performance criteria of the blended mix meet the noted rootzone guidelines. Many inorganic amendments are being sold on the merits of the product itself without regard to the impact (negative or positive) it has in the finished blended rootzone mix.

If a superintendent is considering using an inorganic soil amendment (which are numerous and whose performances vary), he or she should first start by selecting a porous inorganic soil amendment that provides:

• particle size distribution meeting USGA sand-sizing guidelines;
• long-term particle stability;
• contributes to the CEC of the rootzone mix; and
• offers balanced capillary (water) and non-capillary (drainage or air) pore space.

Once the superintendent has selected or narrowed his or her choices, he or she should submit samples of the desired sand and inorganic soil amendments to an A2L2-accredited physical soil-testing lab for a complete rootzone mix development analysis. Reviewing and understanding the results of the blended mix performance characteristics are critical in the final selection and development of the rootzone mix.

As with your health, don't leave the selection and mix ratio of your porous inorganic soil amendment to chance. Test and understand your rootzone mix numbers. Knowing the performance characteristics of your rootzone mix will provide you the foundation for healthy greens.