GRAVEL FOR PUTTING GREEN: What is the best kind of gravel for a putting green? Someone told me that calcium carbonate breaks down. Palm Beach Gardens

ANSWER: The gravel drainage blanket must support a false water table in the medium sand root layer above.  To accomplish this, particles in both layers must be sized to provide a sharp boundary.  Some calcium carbonates are too soft and crumble under construction traffic, resulting in particles sizes too small in the gravel layer.

Over years, calcium carbonate can also weather due to solution.  There is nothing wrong with calcium carbonate gravel, as long as it meets the appropriate tests for weathering and mechanical stability. According to Mr. Powell Gaines, of the Tifton Physical Soil Testing Laboratory (Tifton, Georgia), most quarries serving Florida currently meet the requirement.  If tests are not available from your quarry, the gravel source should be tested.